Let the InvocationService drive the clock instead of having its own ticking loop.

Also use sleep_until to get intervals indendant of invoke cost as long as cost is within interval.
This also also saves a clock sample and simplifies implementation.

36 files changed, 131 insertions, 151 deletions

diff --git a/searchcore/src/apps/tests/persistenceconformance_test.cpp b/searchcore/src/apps/tests/persistenceconformance_test.cpp
index fd0ace21955..4369666591f 100644
--- a/searchcore/src/apps/tests/persistenceconformance_test.cpp
+++ b/searchcore/src/apps/tests/persistenceconformance_test.cpp
@@ -171,7 +171,6 @@ private:
     DummyFileHeaderContext    _fileHeaderContext;
     vespalib::string          _tlsSpec;
     matching::QueryLimiter    _queryLimiter;
-    vespalib::Clock           _clock;
     mutable DummyWireService      _metricsWireService;
     mutable MemoryConfigStores    _config_stores;
     vespalib::ThreadStackExecutor _summaryExecutor;
@@ -209,7 +208,7 @@ public:
                                                   tuneFileDocDB, HwInfo());
         mgr.forwardConfig(b);
         mgr.nextGeneration(_shared_service.transport(), 0ms);
-        return DocumentDB::create(_baseDir, mgr.getConfig(), _tlsSpec, _queryLimiter, _clock, docType, bucketSpace,
+        return DocumentDB::create(_baseDir, mgr.getConfig(), _tlsSpec, _queryLimiter, docType, bucketSpace,
                                   *b->getProtonConfigSP(), const_cast<DocumentDBFactory &>(*this),
                                   _shared_service, _bucketExecutor, _tls, _metricsWireService,
                                   _fileHeaderContext, _config_stores.getConfigStore(docType.toString()),
@@ -223,7 +222,6 @@ DocumentDBFactory::DocumentDBFactory(const vespalib::string &baseDir, int tlsLis
       _fileHeaderContext(),
       _tlsSpec(vespalib::make_string("tcp/localhost:%d", tlsListenPort)),
       _queryLimiter(),
-      _clock(),
       _metricsWireService(),
       _summaryExecutor(8, 128_Ki),
       _shared_service(_summaryExecutor, _summaryExecutor),
diff --git a/searchcore/src/tests/grouping/grouping.cpp b/searchcore/src/tests/grouping/grouping.cpp
index 65c7361953e..a08d4703814 100644
--- a/searchcore/src/tests/grouping/grouping.cpp
+++ b/searchcore/src/tests/grouping/grouping.cpp
@@ -10,6 +10,7 @@
 #include <vespa/searchcore/grouping/groupingsession.h>
 #include <vespa/searchcore/proton/matching/sessionmanager.h>
 #include <vespa/searchlib/test/mock_attribute_context.h>
+#include <vespa/vespalib/util/testclock.h>
 #include <iostream>
 #include <vespa/vespalib/testkit/test_kit.h>
 #include <vespa/log/log.h>
@@ -111,7 +112,7 @@ private:
 };
 
 struct DoomFixture {
-    vespalib::Clock clock;
+    vespalib::TestClock clock;
     steady_time timeOfDoom;
     DoomFixture() : clock(), timeOfDoom(steady_time::max()) {}
 };
@@ -168,7 +169,7 @@ TEST_F("testGroupingContextInitialization", DoomFixture()) {
     nos << (uint32_t)1;
     baseRequest.serialize(nos);
 
-    GroupingContext context(f1.clock, f1.timeOfDoom, os.data(), os.size());
+    GroupingContext context(f1.clock.clock(), f1.timeOfDoom, os.data(), os.size());
     ASSERT_TRUE(!context.empty());
     GroupingContext::GroupingList list = context.getGroupingList();
     ASSERT_TRUE(list.size() == 1);
@@ -198,7 +199,7 @@ TEST_F("testGroupingContextUsage", DoomFixture()) {
 
     GroupingContext::GroupingPtr r1(new Grouping(request1));
     GroupingContext::GroupingPtr r2(new Grouping(request2));
-    GroupingContext context(f1.clock, f1.timeOfDoom);
+    GroupingContext context(f1.clock.clock(), f1.timeOfDoom);
     ASSERT_TRUE(context.empty());
     context.addGrouping(r1);
     ASSERT_TRUE(context.getGroupingList().size() == 1);
@@ -220,7 +221,7 @@ TEST_F("testGroupingContextSerializing", DoomFixture()) {
     nos << (uint32_t)1;
     baseRequest.serialize(nos);
 
-    GroupingContext context(f1.clock, f1.timeOfDoom);
+    GroupingContext context(f1.clock.clock(), f1.timeOfDoom);
     GroupingContext::GroupingPtr bp(new Grouping(baseRequest));
     context.addGrouping(bp);
     context.serialize();
@@ -238,7 +239,7 @@ TEST_F("testGroupingManager", DoomFixture()) {
             .addLevel(createGL(MU<AttributeNode>("attr1"), MU<AttributeNode>("attr2")))
             .addLevel(createGL(MU<AttributeNode>("attr2"), MU<AttributeNode>("attr3")));
 
-    GroupingContext context(f1.clock, f1.timeOfDoom);
+    GroupingContext context(f1.clock.clock(), f1.timeOfDoom);
     GroupingContext::GroupingPtr bp(new Grouping(request1));
     context.addGrouping(bp);
     GroupingManager manager(context);
@@ -273,7 +274,7 @@ TEST_F("testGroupingSession", DoomFixture()) {
 
     GroupingContext::GroupingPtr r1(new Grouping(request1));
     GroupingContext::GroupingPtr r2(new Grouping(request2));
-    GroupingContext initContext(f1.clock, f1.timeOfDoom);
+    GroupingContext initContext(f1.clock.clock(), f1.timeOfDoom);
     initContext.addGrouping(r1);
     initContext.addGrouping(r2);
     SessionId id("foo");
@@ -305,7 +306,7 @@ TEST_F("testGroupingSession", DoomFixture()) {
     }
     // Test second pass
     {
-        GroupingContext context(f1.clock, f1.timeOfDoom);
+        GroupingContext context(f1.clock.clock(), f1.timeOfDoom);
         GroupingContext::GroupingPtr r(new Grouping(request1));
         r->setFirstLevel(1);
         r->setLastLevel(1);
@@ -316,7 +317,7 @@ TEST_F("testGroupingSession", DoomFixture()) {
     }
     // Test last pass. Session should be marked as finished
     {
-        GroupingContext context(f1.clock, f1.timeOfDoom);
+        GroupingContext context(f1.clock.clock(), f1.timeOfDoom);
         GroupingContext::GroupingPtr r(new Grouping(request1));
         r->setFirstLevel(2);
         r->setLastLevel(2);
@@ -340,7 +341,7 @@ TEST_F("testEmptySessionId", DoomFixture()) {
             .addLevel(createGL(MU<AttributeNode>("attr2"), MU<AttributeNode>("attr3")));
 
     GroupingContext::GroupingPtr r1(new Grouping(request1));
-    GroupingContext initContext(f1.clock, f1.timeOfDoom);
+    GroupingContext initContext(f1.clock.clock(), f1.timeOfDoom);
     initContext.addGrouping(r1);
     SessionId id;
 
@@ -373,7 +374,7 @@ TEST_F("testSessionManager", DoomFixture()) {
                                                .setResult(Int64ResultNode(0))));
 
     GroupingContext::GroupingPtr r1(new Grouping(request1));
-    GroupingContext initContext(f1.clock, f1.timeOfDoom);
+    GroupingContext initContext(f1.clock.clock(), f1.timeOfDoom);
     initContext.addGrouping(r1);
 
     SessionManager mgr(2);
@@ -431,7 +432,7 @@ TEST_F("test grouping fork/join", DoomFixture()) {
            .setLastLevel(1);
 
     GroupingContext::GroupingPtr g1(new Grouping(request));
-    GroupingContext context(f1.clock, f1.timeOfDoom);
+    GroupingContext context(f1.clock.clock(), f1.timeOfDoom);
     context.addGrouping(g1);
     GroupingSession session(SessionId(), context, world.attributeContext);
     session.prepareThreadContextCreation(4);
@@ -473,8 +474,8 @@ TEST_F("test session timeout", DoomFixture()) {
     SessionId id1("foo");
     SessionId id2("bar");
 
-    GroupingContext initContext1(f1.clock, steady_time(duration(10)));
-    GroupingContext initContext2(f1.clock, steady_time(duration(20)));
+    GroupingContext initContext1(f1.clock.clock(), steady_time(duration(10)));
+    GroupingContext initContext2(f1.clock.clock(), steady_time(duration(20)));
     GroupingSession::UP s1(new GroupingSession(id1, initContext1, world.attributeContext));
     GroupingSession::UP s2(new GroupingSession(id2, initContext2, world.attributeContext));
     mgr.insert(std::move(s1));
diff --git a/searchcore/src/tests/proton/docsummary/docsummary.cpp b/searchcore/src/tests/proton/docsummary/docsummary.cpp
index faea1cc8b7c..ef8dc17dc0e 100644
--- a/searchcore/src/tests/proton/docsummary/docsummary.cpp
+++ b/searchcore/src/tests/proton/docsummary/docsummary.cpp
@@ -183,7 +183,6 @@ public:
     storage::spi::dummy::DummyBucketExecutor _bucketExecutor;
     bool _mkdirOk;
     matching::QueryLimiter _queryLimiter;
-    vespalib::Clock _clock;
     DummyWireService _dummy;
     ::config::DirSpec _spec;
     DocumentDBConfigHelper _configMgr;
@@ -204,7 +203,6 @@ public:
           _bucketExecutor(2),
           _mkdirOk(FastOS_File::MakeDirectory("tmpdb")),
           _queryLimiter(),
-          _clock(),
           _dummy(),
           _spec(TEST_PATH("")),
           _configMgr(_spec, getDocTypeName()),
@@ -227,7 +225,7 @@ public:
         if (! FastOS_File::MakeDirectory((std::string("tmpdb/") + docTypeName).c_str())) {
             LOG_ABORT("should not be reached");
         }
-        _ddb = DocumentDB::create("tmpdb", _configMgr.getConfig(), "tcp/localhost:9013", _queryLimiter, _clock,
+        _ddb = DocumentDB::create("tmpdb", _configMgr.getConfig(), "tcp/localhost:9013", _queryLimiter,
                                   DocTypeName(docTypeName), makeBucketSpace(), *b->getProtonConfigSP(), *this,
                                   _shared_service, _bucketExecutor, _tls, _dummy, _fileHeaderContext,
                                   std::make_unique<MemoryConfigStore>(),
diff --git a/searchcore/src/tests/proton/documentdb/configurer/configurer_test.cpp b/searchcore/src/tests/proton/documentdb/configurer/configurer_test.cpp
index 0e9eb926514..9e77047e578 100644
--- a/searchcore/src/tests/proton/documentdb/configurer/configurer_test.cpp
+++ b/searchcore/src/tests/proton/documentdb/configurer/configurer_test.cpp
@@ -28,6 +28,7 @@
 #include <vespa/vespalib/io/fileutil.h>
 #include <vespa/vespalib/util/size_literals.h>
 #include <vespa/vespalib/util/threadstackexecutor.h>
+#include <vespa/vespalib/util/testclock.h>
 
 using namespace config;
 using namespace document;
@@ -146,7 +147,7 @@ struct MyDocumentDBReferenceResolver : public IDocumentDBReferenceResolver {
 
 struct Fixture
 {
-    vespalib::Clock _clock;
+    vespalib::TestClock _clock;
     matching::QueryLimiter _queryLimiter;
     EmptyConstantValueFactory _constantValueFactory;
     ConstantValueRepo _constantValueRepo;
@@ -175,7 +176,7 @@ Fixture::Fixture()
     vespalib::mkdir(BASE_DIR);
     initViewSet(_views);
     _configurer = std::make_unique<Configurer>(_views._summaryMgr, _views.searchView, _views.feedView, _queryLimiter,
-                                               _constantValueRepo, _clock, "test", 0);
+                                               _constantValueRepo, _clock.clock(), "test", 0);
 }
 Fixture::~Fixture() = default;
 
@@ -184,7 +185,7 @@ Fixture::initViewSet(ViewSet &views)
 {
     using IndexManager = proton::index::IndexManager;
     using IndexConfig = proton::index::IndexConfig;
-    auto matchers = std::make_shared<Matchers>(_clock, _queryLimiter, _constantValueRepo);
+    auto matchers = std::make_shared<Matchers>(_clock.clock(), _queryLimiter, _constantValueRepo);
     auto indexMgr = make_shared<IndexManager>(BASE_DIR, IndexConfig(searchcorespi::index::WarmupConfig(), 2, 0), Schema(), 1,
                                               views._reconfigurer, views._service.write(), _summaryExecutor,
                                               TuneFileIndexManager(), TuneFileAttributes(), views._fileHeaderContext);
diff --git a/searchcore/src/tests/proton/documentdb/document_subdbs/document_subdbs_test.cpp b/searchcore/src/tests/proton/documentdb/document_subdbs/document_subdbs_test.cpp
index 27636324835..68a92c73b44 100644
--- a/searchcore/src/tests/proton/documentdb/document_subdbs/document_subdbs_test.cpp
+++ b/searchcore/src/tests/proton/documentdb/document_subdbs/document_subdbs_test.cpp
@@ -35,6 +35,7 @@
 #include <vespa/vespalib/util/size_literals.h>
 #include <vespa/vespalib/util/threadstackexecutor.h>
 #include <vespa/vespalib/util/destructor_callbacks.h>
+#include <vespa/vespalib/util/testclock.h>
 #include <vespa/config/subscription/sourcespec.h>
 
 using namespace cloud::config::filedistribution;
@@ -215,9 +216,9 @@ struct MySearchableConfig
 struct MySearchableContext
 {
     MyFastAccessContext _fastUpdCtx;
-    QueryLimiter _queryLimiter;
-    vespalib::Clock _clock;
-    SearchableContext _ctx;
+    QueryLimiter        _queryLimiter;
+    vespalib::TestClock _clock;
+    SearchableContext   _ctx;
     MySearchableContext(IThreadingService &writeService,
                         std::shared_ptr<bucketdb::BucketDBOwner> bucketDB,
                         IBucketDBHandlerInitializer & bucketDBHandlerInitializer);
@@ -236,7 +237,7 @@ MySearchableContext::MySearchableContext(IThreadingService &writeService,
                                          IBucketDBHandlerInitializer & bucketDBHandlerInitializer)
     : _fastUpdCtx(writeService, bucketDB, bucketDBHandlerInitializer),
       _queryLimiter(), _clock(),
-      _ctx(_fastUpdCtx._ctx, _queryLimiter, _clock, writeService.shared())
+      _ctx(_fastUpdCtx._ctx, _queryLimiter, _clock.clock(), writeService.shared())
 {}
 MySearchableContext::~MySearchableContext() = default;
 
diff --git a/searchcore/src/tests/proton/documentdb/documentdb_test.cpp b/searchcore/src/tests/proton/documentdb/documentdb_test.cpp
index c6a8df79a5e..1f3be7511da 100644
--- a/searchcore/src/tests/proton/documentdb/documentdb_test.cpp
+++ b/searchcore/src/tests/proton/documentdb/documentdb_test.cpp
@@ -127,7 +127,6 @@ struct Fixture : public FixtureBase {
     DummyFileHeaderContext _fileHeaderContext;
     TransLogServer _tls;
     matching::QueryLimiter _queryLimiter;
-    vespalib::Clock _clock;
 
     std::unique_ptr<ConfigStore> make_config_store();
     Fixture();
@@ -151,8 +150,7 @@ Fixture::Fixture(bool file_config)
       _db(),
       _fileHeaderContext(),
       _tls(_shared_service.transport(), "tmp", 9014, ".", _fileHeaderContext),
-      _queryLimiter(),
-      _clock()
+      _queryLimiter()
 {
     auto documenttypesConfig = std::make_shared<DocumenttypesConfig>();
     DocumentType docType("typea", 0);
@@ -167,7 +165,7 @@ Fixture::Fixture(bool file_config)
                               tuneFileDocumentDB, HwInfo());
     mgr.forwardConfig(b);
     mgr.nextGeneration(_shared_service.transport(), 0ms);
-    _db = DocumentDB::create(".", mgr.getConfig(), "tcp/localhost:9014", _queryLimiter, _clock, DocTypeName("typea"),
+    _db = DocumentDB::create(".", mgr.getConfig(), "tcp/localhost:9014", _queryLimiter, DocTypeName("typea"),
                              makeBucketSpace(),
                              *b->getProtonConfigSP(), _myDBOwner, _shared_service, _bucketExecutor, _tls, _dummy,
                              _fileHeaderContext, make_config_store(),
diff --git a/searchcore/src/tests/proton/matching/matching_test.cpp b/searchcore/src/tests/proton/matching/matching_test.cpp
index 09bb67dbac9..187c0463da3 100644
--- a/searchcore/src/tests/proton/matching/matching_test.cpp
+++ b/searchcore/src/tests/proton/matching/matching_test.cpp
@@ -8,7 +8,6 @@
 #include <vespa/searchcore/proton/documentmetastore/documentmetastore.h>
 #include <vespa/searchcore/proton/matching/fakesearchcontext.h>
 #include <vespa/searchcore/proton/matching/i_constant_value_repo.h>
-#include <vespa/searchcore/proton/matching/isearchcontext.h>
 #include <vespa/searchcore/proton/matching/matcher.h>
 #include <vespa/searchcore/proton/matching/querynodes.h>
 #include <vespa/searchcore/proton/matching/sessionmanager.h>
@@ -37,6 +36,7 @@
 #include <vespa/eval/eval/tensor_spec.h>
 #include <vespa/eval/eval/value_codec.h>
 #include <vespa/vespalib/objects/nbostream.h>
+#include <vespa/vespalib/util/testclock.h>
 
 #include <vespa/log/log.h>
 LOG_SETUP("matching_test");
@@ -120,7 +120,7 @@ struct MyWorld {
     SessionManager::SP      sessionManager;
     DocumentMetaStore       metaStore;
     MatchingStats           matchingStats;
-    vespalib::Clock         clock;
+    vespalib::TestClock     clock;
     QueryLimiter            queryLimiter;
     EmptyConstantValueRepo  constantValueRepo;
 
@@ -344,7 +344,7 @@ struct MyWorld {
     }
 
     Matcher::SP createMatcher() {
-        return std::make_shared<Matcher>(schema, config, clock, queryLimiter, constantValueRepo, RankingExpressions(), OnnxModels(), 0);
+        return std::make_shared<Matcher>(schema, config, clock.clock(), queryLimiter, constantValueRepo, RankingExpressions(), OnnxModels(), 0);
     }
 
     struct MySearchHandler : ISearchHandler {
diff --git a/searchcore/src/tests/proton/matching/request_context/request_context_test.cpp b/searchcore/src/tests/proton/matching/request_context/request_context_test.cpp
index 8ede5277d71..191c1718f61 100644
--- a/searchcore/src/tests/proton/matching/request_context/request_context_test.cpp
+++ b/searchcore/src/tests/proton/matching/request_context/request_context_test.cpp
@@ -6,6 +6,7 @@
 #include <vespa/searchcore/proton/matching/requestcontext.h>
 #include <vespa/searchlib/attribute/attribute_blueprint_params.h>
 #include <vespa/searchlib/fef/properties.h>
+#include <vespa/vespalib/util/testclock.h>
 #include <vespa/vespalib/gtest/gtest.h>
 #include <vespa/vespalib/objects/nbostream.h>
 
@@ -29,7 +30,7 @@ public:
 
 class RequestContextTest : public ::testing::Test {
 private:
-    vespalib::Clock        _clock;
+    vespalib::TestClock    _clock;
     vespalib::Doom         _doom;
     MyAttributeContext     _attr_ctx;
     Properties             _props;
@@ -45,7 +46,7 @@ private:
 public:
     RequestContextTest()
         : _clock(),
-          _doom(_clock, vespalib::steady_time(), vespalib::steady_time(), false),
+          _doom(_clock.clock(), vespalib::steady_time(), vespalib::steady_time(), false),
           _attr_ctx(),
           _props(),
           _request_ctx(_doom, _attr_ctx, _props, AttributeBlueprintParams()),
diff --git a/searchcore/src/vespa/searchcore/bmcluster/bm_node.cpp b/searchcore/src/vespa/searchcore/bmcluster/bm_node.cpp
index 85fd304f395..86dc38159e8 100644
--- a/searchcore/src/vespa/searchcore/bmcluster/bm_node.cpp
+++ b/searchcore/src/vespa/searchcore/bmcluster/bm_node.cpp
@@ -451,7 +451,6 @@ class MyBmNode : public BmNode
     int                                        _distributor_status_port;
     vespalib::string                           _tls_spec;
     proton::matching::QueryLimiter             _query_limiter;
-    vespalib::Clock                            _clock;
     proton::DummyWireService                   _metrics_wire_service;
     proton::MemoryConfigStores                 _config_stores;
     vespalib::ThreadStackExecutor              _summary_executor;
@@ -516,7 +515,6 @@ MyBmNode::MyBmNode(const vespalib::string& base_dir, int base_port, uint32_t nod
       _distributor_status_port(port_number(base_port, PortBias::DISTRIBUTOR_STATUS_PORT)),
       _tls_spec(vespalib::make_string("tcp/localhost:%d", _tls_listen_port)),
       _query_limiter(),
-      _clock(),
       _metrics_wire_service(),
       _config_stores(),
       _summary_executor(8, 128_Ki),
@@ -591,7 +589,7 @@ MyBmNode::create_document_db(const BmClusterParams& params)
                                                               tuneFileDocDB, HwInfo());
     mgr.forwardConfig(bootstrap_config);
     mgr.nextGeneration(_shared_service.transport(), 0ms);
-    _document_db = DocumentDB::create(_base_dir, mgr.getConfig(), _tls_spec, _query_limiter, _clock, _doc_type_name,
+    _document_db = DocumentDB::create(_base_dir, mgr.getConfig(), _tls_spec, _query_limiter, _doc_type_name,
                                       _bucket_space, *bootstrap_config->getProtonConfigSP(), _document_db_owner,
                                       _shared_service, *_persistence_engine, _tls,
                                       _metrics_wire_service, _file_header_context,
diff --git a/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.cpp b/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.cpp
index 435b6f718c7..56c3a1c761b 100644
--- a/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.cpp
+++ b/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.cpp
@@ -1,12 +1,14 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
 #include "fakesearchcontext.h"
+#include <vespa/vespalib/util/testclock.h>
+
 
 namespace proton::matching {
 
 FakeSearchContext::FakeSearchContext(size_t initialNumDocs)
-    : _clock(),
-      _doom(_clock, vespalib::steady_time()),
+    : _clock(std::make_unique<vespalib::TestClock>()),
+      _doom(_clock->clock(), vespalib::steady_time()),
       _selector(std::make_shared<search::FixedSourceSelector>(0, "fs", initialNumDocs)),
       _indexes(std::make_shared<IndexCollection>(_selector)),
       _attrSearchable(),
diff --git a/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.h b/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.h
index 254f473c4ae..659bfc6c6d8 100644
--- a/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.h
+++ b/searchcore/src/vespa/searchcore/proton/matching/fakesearchcontext.h
@@ -11,6 +11,7 @@
 #include <map>
 #include <vector>
 
+namespace vespalib { class TestClock; }
 namespace proton::matching {
 
 using searchcorespi::FakeIndexSearchable;
@@ -23,7 +24,7 @@ public:
     typedef search::queryeval::FakeSearchable FakeSearchable;
 
 private:
-    vespalib::Clock                        _clock;
+    std::unique_ptr<vespalib::TestClock>   _clock;
     vespalib::Doom                         _doom;
     search::queryeval::ISourceSelector::SP _selector;
     IndexCollection::SP                    _indexes;
diff --git a/searchcore/src/vespa/searchcore/proton/matching/matcher.cpp b/searchcore/src/vespa/searchcore/proton/matching/matcher.cpp
index 4d94d2629fe..e945bbb850b 100644
--- a/searchcore/src/vespa/searchcore/proton/matching/matcher.cpp
+++ b/searchcore/src/vespa/searchcore/proton/matching/matcher.cpp
@@ -150,7 +150,7 @@ Matcher::create_match_tools_factory(const search::engine::Request &request, ISea
                         : _stats.softDoomFactor())
                     : 0.95;
     vespalib::duration safeLeft = std::chrono::duration_cast<vespalib::duration>(request.getTimeLeft() * factor);
-    vespalib::steady_time safeDoom(_clock.getTimeNSAssumeRunning() + safeLeft);
+    vespalib::steady_time safeDoom(_clock.getTimeNS() + safeLeft);
     if (softTimeoutEnabled) {
         LOG(debug, "Soft-timeout computed factor=%1.3f, used factor=%1.3f, userSupplied=%d, softTimeout=%" PRId64,
                    _stats.softDoomFactor(), factor, hasFactorOverride, vespalib::count_ns(safeLeft));
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp b/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
index cf6193555e5..37a17fecfc1 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
@@ -140,7 +140,6 @@ DocumentDB::create(const vespalib::string &baseDir,
                    DocumentDBConfig::SP currentSnapshot,
                    const vespalib::string &tlsSpec,
                    matching::QueryLimiter &queryLimiter,
-                   const vespalib::Clock &clock,
                    const DocTypeName &docTypeName,
                    document::BucketSpace bucketSpace,
                    const ProtonConfig &protonCfg,
@@ -155,7 +154,7 @@ DocumentDB::create(const vespalib::string &baseDir,
                    const HwInfo &hwInfo)
 {
     return DocumentDB::SP(
-            new DocumentDB(baseDir, std::move(currentSnapshot), tlsSpec, queryLimiter, clock, docTypeName, bucketSpace,
+            new DocumentDB(baseDir, std::move(currentSnapshot), tlsSpec, queryLimiter, docTypeName, bucketSpace,
                            protonCfg, owner, shared_service, bucketExecutor, tlsWriterFactory,
                            metricsWireService, fileHeaderContext, std::move(config_store), initializeThreads, hwInfo));
 }
@@ -163,7 +162,6 @@ DocumentDB::DocumentDB(const vespalib::string &baseDir,
                        DocumentDBConfig::SP configSnapshot,
                        const vespalib::string &tlsSpec,
                        matching::QueryLimiter &queryLimiter,
-                       const vespalib::Clock &clock,
                        const DocTypeName &docTypeName,
                        document::BucketSpace bucketSpace,
                        const ProtonConfig &protonCfg,
@@ -219,7 +217,7 @@ DocumentDB::DocumentDB(const vespalib::string &baseDir,
       _transient_usage_provider(std::make_shared<DocumentDBResourceUsageProvider>(*this)),
       _feedHandler(std::make_unique<FeedHandler>(_writeService, tlsSpec, docTypeName, *this, _writeFilter, *this, tlsWriterFactory)),
       _subDBs(*this, *this, *_feedHandler, _docTypeName, _writeService, shared_service.warmup(), fileHeaderContext,
-              metricsWireService, getMetrics(), queryLimiter, clock, _configMutex, _baseDir, hwInfo),
+              metricsWireService, getMetrics(), queryLimiter, shared_service.clock(), _configMutex, _baseDir, hwInfo),
       _maintenanceController(shared_service.transport(), _writeService.master(), shared_service.shared(), _refCount, _docTypeName),
       _jobTrackers(),
       _calc(),
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb.h b/searchcore/src/vespa/searchcore/proton/server/documentdb.h
index 2030e6ffac9..e3d467fc3c1 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentdb.h
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb.h
@@ -197,7 +197,6 @@ private:
                DocumentDBConfig::SP currentSnapshot,
                const vespalib::string &tlsSpec,
                matching::QueryLimiter &queryLimiter,
-               const vespalib::Clock &clock,
                const DocTypeName &docTypeName,
                document::BucketSpace bucketSpace,
                const ProtonConfig &protonCfg,
@@ -228,7 +227,6 @@ public:
            DocumentDBConfig::SP currentSnapshot,
            const vespalib::string &tlsSpec,
            matching::QueryLimiter &queryLimiter,
-           const vespalib::Clock &clock,
            const DocTypeName &docTypeName,
            document::BucketSpace bucketSpace,
            const ProtonConfig &protonCfg,
diff --git a/searchcore/src/vespa/searchcore/proton/server/executorthreadingservice.cpp b/searchcore/src/vespa/searchcore/proton/server/executorthreadingservice.cpp
index a268a6eac87..d6ecc6dd2d3 100644
--- a/searchcore/src/vespa/searchcore/proton/server/executorthreadingservice.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/executorthreadingservice.cpp
@@ -13,6 +13,7 @@ using vespalib::CpuUsage;
 using vespalib::SequencedTaskExecutor;
 using vespalib::SingleExecutor;
 using vespalib::SyncableThreadExecutor;
+using vespalib::steady_time;
 using OptimizeFor = vespalib::Executor::OptimizeFor;
 using SharedFieldWriterExecutor = proton::ThreadingServiceConfig::SharedFieldWriterExecutor;
 
diff --git a/searchcore/src/vespa/searchcore/proton/server/i_shared_threading_service.h b/searchcore/src/vespa/searchcore/proton/server/i_shared_threading_service.h
index a467f9bc320..12377fd25e0 100644
--- a/searchcore/src/vespa/searchcore/proton/server/i_shared_threading_service.h
+++ b/searchcore/src/vespa/searchcore/proton/server/i_shared_threading_service.h
@@ -7,6 +7,7 @@ namespace vespalib {
 class ISequencedTaskExecutor;
 class ThreadExecutor;
 class InvokeService;
+class Clock;
 }
 
 namespace proton {
@@ -51,6 +52,11 @@ public:
      * Returns a shared transport object that can be utilized by multiple services.
      */
     virtual FNET_Transport & transport() = 0;
+
+    /**
+     * Return a very cheap clock.
+     */
+    virtual const vespalib::Clock & clock() const = 0;
 };
 
 }
diff --git a/searchcore/src/vespa/searchcore/proton/server/proton.cpp b/searchcore/src/vespa/searchcore/proton/server/proton.cpp
index 974c2522565..9bf6d19231e 100644
--- a/searchcore/src/vespa/searchcore/proton/server/proton.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/proton.cpp
@@ -241,7 +241,6 @@ Proton::Proton(FastOS_ThreadPool & threadPool, FNET_Transport & transport, const
       _shared_service(),
       _compile_cache_executor_binding(),
       _queryLimiter(),
-      _clock(),
       _distributionKey(-1),
       _isInitializing(true),
       _abortInit(false),
@@ -278,7 +277,6 @@ Proton::init(const BootstrapConfig::SP & configSnapshot)
     setBucketCheckSumType(protonConfig);
     setFS4Compression(protonConfig);
     _shared_service = std::make_unique<SharedThreadingService>(SharedThreadingServiceConfig::make(protonConfig, hwInfo.cpu()), _transport);
-    _clock.start(_shared_service->invokeService());
     _diskMemUsageSampler = std::make_unique<DiskMemUsageSampler>(_shared_service->transport(), protonConfig.basedir,
                                                                  diskMemUsageSamplerConfig(protonConfig, hwInfo));
 
@@ -473,7 +471,6 @@ Proton::~Proton()
     _persistenceEngine.reset();
     _tls.reset();
     _compile_cache_executor_binding.reset();
-    _clock.stop();
     _shared_service.reset();
     LOG(debug, "Explicit destructor done");
 }
@@ -610,7 +607,6 @@ Proton::addDocumentDB(const document::DocumentType &docType,
                                   documentDBConfig,
                                   config.tlsspec,
                                   _queryLimiter,
-                                  _clock,
                                   docTypeName,
                                   bucketSpace,
                                   config,
diff --git a/searchcore/src/vespa/searchcore/proton/server/proton.h b/searchcore/src/vespa/searchcore/proton/server/proton.h
index 73b8ae83ef2..58c9a8bda3e 100644
--- a/searchcore/src/vespa/searchcore/proton/server/proton.h
+++ b/searchcore/src/vespa/searchcore/proton/server/proton.h
@@ -111,7 +111,6 @@ private:
     std::unique_ptr<SharedThreadingService> _shared_service;
     vespalib::eval::CompileCache::ExecutorBinding::UP _compile_cache_executor_binding;
     matching::QueryLimiter          _queryLimiter;
-    vespalib::Clock                 _clock;
     uint32_t                        _distributionKey;
     bool                            _isInitializing;
     bool                            _abortInit;
diff --git a/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.cpp b/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.cpp
index b36dce23e28..cba2c1d458f 100644
--- a/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.cpp
@@ -3,13 +3,11 @@
 #include "shared_threading_service.h"
 #include <vespa/vespalib/util/blockingthreadstackexecutor.h>
 #include <vespa/vespalib/util/cpu_usage.h>
-#include <vespa/vespalib/util/isequencedtaskexecutor.h>
 #include <vespa/vespalib/util/sequencedtaskexecutor.h>
 #include <vespa/vespalib/util/size_literals.h>
-#include <vespa/fnet/transport.h>
-#include <vespa/fastos/thread.h>
 
 using vespalib::CpuUsage;
+using vespalib::steady_time;
 
 VESPA_THREAD_STACK_TAG(proton_field_writer_executor)
 VESPA_THREAD_STACK_TAG(proton_shared_executor)
@@ -28,7 +26,8 @@ SharedThreadingService::SharedThreadingService(const SharedThreadingServiceConfi
       _field_writer(),
       _invokeService(std::max(vespalib::adjustTimeoutByDetectedHz(1ms),
                               cfg.field_writer_config().reactionTime())),
-      _invokeRegistrations()
+      _invokeRegistrations(),
+      _clock(_invokeService.nowPtr())
 {
     const auto& fw_cfg = cfg.field_writer_config();
     if (fw_cfg.shared_field_writer() == SharedFieldWriterExecutor::DOCUMENT_DB) {
diff --git a/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.h b/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.h
index 349dcc2d0ce..463823f10cb 100644
--- a/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.h
+++ b/searchcore/src/vespa/searchcore/proton/server/shared_threading_service.h
@@ -5,6 +5,7 @@
 #include "shared_threading_service_config.h"
 #include <vespa/vespalib/util/threadstackexecutor.h>
 #include <vespa/vespalib/util/syncable.h>
+#include <vespa/vespalib/util/clock.h>
 #include <vespa/vespalib/util/invokeserviceimpl.h>
 #include <memory>
 
@@ -22,7 +23,7 @@ private:
     std::unique_ptr<vespalib::ISequencedTaskExecutor> _field_writer;
     vespalib::InvokeServiceImpl                       _invokeService;
     std::vector<Registration>                         _invokeRegistrations;
-
+    vespalib::Clock                                   _clock;
 public:
     SharedThreadingService(const SharedThreadingServiceConfig& cfg, FNET_Transport & transport);
     ~SharedThreadingService() override;
@@ -35,6 +36,7 @@ public:
     vespalib::ISequencedTaskExecutor* field_writer() override { return _field_writer.get(); }
     vespalib::InvokeService & invokeService() override { return _invokeService; }
     FNET_Transport & transport() override { return _transport; }
+    const vespalib::Clock & clock() const override { return _clock; }
 };
 
 }
diff --git a/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.cpp b/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.cpp
index d695f4d8dc7..55f77ff41ea 100644
--- a/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.cpp
+++ b/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.cpp
@@ -8,7 +8,8 @@ MockSharedThreadingService::MockSharedThreadingService(ThreadExecutor& warmup_in
     : _warmup(warmup_in),
       _shared(shared_in),
       _invokeService(10ms),
-      _transport()
+      _transport(),
+      _clock(_invokeService.nowPtr())
 {
 }
 
diff --git a/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.h b/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.h
index 7db208fa3ef..35c8ee46de5 100644
--- a/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.h
+++ b/searchcore/src/vespa/searchcore/proton/test/mock_shared_threading_service.h
@@ -4,6 +4,7 @@
 #include "transport_helper.h"
 #include <vespa/searchcore/proton/server/i_shared_threading_service.h>
 #include <vespa/vespalib/util/invokeserviceimpl.h>
+#include <vespa/vespalib/util/clock.h>
 
 namespace proton {
 
@@ -14,7 +15,7 @@ private:
     ThreadExecutor              & _shared;
     vespalib::InvokeServiceImpl   _invokeService;
     Transport                     _transport;
-
+    vespalib::Clock               _clock;
 public:
     MockSharedThreadingService(ThreadExecutor& warmup_in,
                                ThreadExecutor& shared_in);
@@ -24,6 +25,7 @@ public:
     vespalib::ISequencedTaskExecutor* field_writer() override { return nullptr; }
     vespalib::InvokeService & invokeService() override { return _invokeService; }
     FNET_Transport & transport() override { return _transport.transport(); }
+    const vespalib::Clock & clock() const override { return _clock; }
 };
 
 }
diff --git a/searchlib/src/tests/queryeval/simple_phrase/simple_phrase_test.cpp b/searchlib/src/tests/queryeval/simple_phrase/simple_phrase_test.cpp
index 8879d591f5a..4877072eacd 100644
--- a/searchlib/src/tests/queryeval/simple_phrase/simple_phrase_test.cpp
+++ b/searchlib/src/tests/queryeval/simple_phrase/simple_phrase_test.cpp
@@ -9,6 +9,7 @@
 #include <vespa/searchlib/fef/matchdatalayout.h>
 #include <vespa/searchlib/query/tree/simplequery.h>
 #include <vespa/searchlib/query/weight.h>
+#include <vespa/vespalib/util/testclock.h>
 #include <vespa/vespalib/testkit/testapp.h>
 
 #include <vespa/log/log.h>
@@ -211,8 +212,8 @@ void Test::requireThatIteratorHonorsFutureDoom() {
     test.addTerm("foo", 0).addTerm("bar", 1);
 
     test.fetchPostings(false);
-    vespalib::Clock clock;
-    vespalib::Doom futureDoom(clock, vespalib::steady_time::max());
+    vespalib::TestClock clock;
+    vespalib::Doom futureDoom(clock.clock(), vespalib::steady_time::max());
     unique_ptr<SearchIterator> search(test.createSearch(false));
     static_cast<SimplePhraseSearch &>(*search).setDoom(&futureDoom);
     EXPECT_TRUE(!search->seek(1u));
@@ -225,8 +226,8 @@ void Test::requireThatIteratorHonorsDoom() {
     test.addTerm("foo", 0).addTerm("bar", 1);
 
     test.fetchPostings(false);
-    vespalib::Clock clock;
-    vespalib::Doom futureDoom(clock, vespalib::steady_time());
+    vespalib::TestClock clock;
+    vespalib::Doom futureDoom(clock.clock(), vespalib::steady_time());
     unique_ptr<SearchIterator> search(test.createSearch(false));
     static_cast<SimplePhraseSearch &>(*search).setDoom(&futureDoom);
     EXPECT_TRUE(!search->seek(1u));
diff --git a/searchlib/src/tests/sortspec/multilevelsort.cpp b/searchlib/src/tests/sortspec/multilevelsort.cpp
index 576e1d1336c..88b105ec80c 100644
--- a/searchlib/src/tests/sortspec/multilevelsort.cpp
+++ b/searchlib/src/tests/sortspec/multilevelsort.cpp
@@ -7,6 +7,7 @@
 #include <vespa/searchlib/attribute/attributecontext.h>
 #include <vespa/searchlib/attribute/attributemanager.h>
 #include <vespa/searchlib/uca/ucaconverter.h>
+#include <vespa/vespalib/util/testclock.h>
 #include <vespa/vespalib/testkit/testapp.h>
 #include <vespa/log/log.h>
 LOG_SETUP("multilevelsort_test");
@@ -14,13 +15,9 @@ LOG_SETUP("multilevelsort_test");
 using namespace search;
 
 typedef FastS_SortSpec::VectorRef VectorRef;
-typedef IntegerAttributeTemplate<uint8_t>  Uint8;
 typedef IntegerAttributeTemplate<int8_t>   Int8;
-typedef IntegerAttributeTemplate<uint16_t> Uint16;
 typedef IntegerAttributeTemplate<int16_t>  Int16;
-typedef IntegerAttributeTemplate<uint32_t> Uint32;
 typedef IntegerAttributeTemplate<int32_t>  Int32;
-typedef IntegerAttributeTemplate<uint64_t> Uint64;
 typedef IntegerAttributeTemplate<int64_t>  Int64;
 typedef FloatingPointAttributeTemplate<float>  Float;
 typedef FloatingPointAttributeTemplate<double> Double;
@@ -239,8 +236,8 @@ MultilevelSortTest::sortAndCheck(const std::vector<Spec> &spec, uint32_t num,
         hits[i]._rankValue = getRandomValue<uint32_t>();
     }
 
-    vespalib::Clock clock;
-    vespalib::Doom doom(clock, vespalib::steady_time::max());
+    vespalib::TestClock clock;
+    vespalib::Doom doom(clock.clock(), vespalib::steady_time::max());
     search::uca::UcaConverterFactory ucaFactory;
     FastS_SortSpec sorter(7, doom, ucaFactory, _sortMethod);
     // init sorter with sort data
@@ -396,8 +393,8 @@ TEST("require that all sort methods behave the same")
 }
 
 TEST("test that [docid] translates to [lid][paritionid]") {
-    vespalib::Clock clock;
-    vespalib::Doom doom(clock, vespalib::steady_time::max());
+    vespalib::TestClock clock;
+    vespalib::Doom doom(clock.clock(), vespalib::steady_time::max());
     search::uca::UcaConverterFactory ucaFactory;
     FastS_SortSpec asc(7, doom, ucaFactory);
     RankedHit hits[2] = {RankedHit(91, 0.0), RankedHit(3, 2.0)};
diff --git a/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.cpp b/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.cpp
index ea4cbf84550..a123d3f6cd1 100644
--- a/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.cpp
+++ b/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.cpp
@@ -1,12 +1,14 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
 #include "fake_requestcontext.h"
+#include <vespa/vespalib/util/testclock.h>
+
 
 namespace search::queryeval {
 
 FakeRequestContext::FakeRequestContext(attribute::IAttributeContext * context, vespalib::steady_time softDoom, vespalib::steady_time hardDoom)
-    : _clock(),
-      _doom(_clock, softDoom, hardDoom, false),
+    : _clock(std::make_unique<vespalib::TestClock>()),
+      _doom(_clock->clock(), softDoom, hardDoom, false),
       _attributeContext(context),
       _query_tensor_name(),
       _query_tensor(),
diff --git a/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.h b/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.h
index 25a4fa559e0..a492f055cdb 100644
--- a/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.h
+++ b/searchlib/src/vespa/searchlib/queryeval/fake_requestcontext.h
@@ -13,6 +13,7 @@
 #include <vespa/vespalib/util/doom.h>
 #include <limits>
 
+namespace vespalib { class TestClock; }
 namespace search::queryeval {
 
 class FakeRequestContext : public IRequestContext
@@ -47,7 +48,7 @@ public:
     const search::attribute::AttributeBlueprintParams& get_attribute_blueprint_params() const override;
 
 private:
-    vespalib::Clock _clock;
+    std::unique_ptr<vespalib::TestClock> _clock;
     const vespalib::Doom _doom;
     attribute::IAttributeContext *_attributeContext;
     vespalib::string _query_tensor_name;
diff --git a/staging_vespalib/src/tests/clock/clock_benchmark.cpp b/staging_vespalib/src/tests/clock/clock_benchmark.cpp
index c8d3e2a5aff..a51d83ae4dc 100644
--- a/staging_vespalib/src/tests/clock/clock_benchmark.cpp
+++ b/staging_vespalib/src/tests/clock/clock_benchmark.cpp
@@ -139,17 +139,16 @@ main(int , char *argv[])
     NSVolatile nsVolatile;
     NSAtomic nsAtomic;
     vespalib::InvokeServiceImpl invoker(vespalib::from_s(1.0/frequency));
-    Clock clock;
+    Clock clock(invoker.nowPtr());
     TestClock nsClock(nsValue, 1.0/frequency);
     TestClock nsVolatileClock(nsVolatile, 1.0/frequency);
     TestClock nsAtomicClock(nsAtomic, 1.0/frequency);
-    clock.start(invoker);
     assert(pool.NewThread(&nsClock, nullptr) != nullptr);
     assert(pool.NewThread(&nsVolatileClock, nullptr) != nullptr);
     assert(pool.NewThread(&nsAtomicClock, nullptr) != nullptr);
 
     benchmark("vespalib::Clock", pool, samples, numThreads, [&clock]() {
-        return clock.getTimeNSAssumeRunning();
+        return clock.getTimeNS();
     });
     benchmark("uint64_t", pool, samples, numThreads, [&nsValue]() {
         return steady_time (duration(nsValue._value));
@@ -175,6 +174,5 @@ main(int , char *argv[])
     });
 
     pool.Close();
-    clock.stop();
     return 0;
 }
diff --git a/staging_vespalib/src/tests/clock/clock_test.cpp b/staging_vespalib/src/tests/clock/clock_test.cpp
index 2c6cbc0c876..b8ee4d7cc64 100644
--- a/staging_vespalib/src/tests/clock/clock_test.cpp
+++ b/staging_vespalib/src/tests/clock/clock_test.cpp
@@ -19,19 +19,11 @@ void waitForMovement(steady_time start, Clock & clock, vespalib::duration timeou
 
 TEST("Test that clock is ticking forward") {
     vespalib::InvokeServiceImpl invoker(50ms);
-    Clock clock;
-    clock.start(invoker);
+    Clock clock(invoker.nowPtr());
     steady_time start = clock.getTimeNS();
     waitForMovement(start, clock, 10s);
     steady_time stop = clock.getTimeNS();
     EXPECT_TRUE(stop > start);
-    std::this_thread::sleep_for(1s);
-    start = clock.getTimeNS();
-    waitForMovement(start, clock, 10s);
-    clock.stop();
-    steady_time stop2 = clock.getTimeNS();
-    EXPECT_TRUE(stop2 > stop);
-    EXPECT_TRUE(vespalib::count_ms(stop2 - stop) > 1000);
 }
 
 TEST_MAIN() { TEST_RUN_ALL(); }
\ No newline at end of file
diff --git a/staging_vespalib/src/vespa/vespalib/util/CMakeLists.txt b/staging_vespalib/src/vespa/vespalib/util/CMakeLists.txt
index e69dd36d6f5..2912ac2397b 100644
--- a/staging_vespalib/src/vespa/vespalib/util/CMakeLists.txt
+++ b/staging_vespalib/src/vespa/vespalib/util/CMakeLists.txt
@@ -23,6 +23,7 @@ vespa_add_library(staging_vespalib_vespalib_util OBJECT
     shutdownguard.cpp
     scheduledexecutor.cpp
     singleexecutor.cpp
+    testclock.cpp
     xmlserializable.cpp
     xmlstream.cpp
     DEPENDS
diff --git a/staging_vespalib/src/vespa/vespalib/util/clock.cpp b/staging_vespalib/src/vespa/vespalib/util/clock.cpp
index a4b9ed0fd5d..ad9d6d534f9 100644
--- a/staging_vespalib/src/vespa/vespalib/util/clock.cpp
+++ b/staging_vespalib/src/vespa/vespalib/util/clock.cpp
@@ -1,37 +1,16 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
 #include "clock.h"
-#include <vespa/vespalib/util/invokeservice.h>
-
+#include <cassert>
 namespace vespalib {
 
-Clock::Clock() :
-     _timeNS(0u),
-     _running(false),
-     _invokeRegistration()
+Clock::Clock(const std::atomic<steady_time> * source) noexcept
+    : _timeNS(source)
 {
-    setTime();
+    assert(_timeNS != nullptr);
+    static_assert(std::atomic<steady_time>::is_always_lock_free);
 }
 
 Clock::~Clock() = default;
 
-void Clock::setTime() const
-{
-    _timeNS.store(count_ns(steady_clock::now().time_since_epoch()), std::memory_order_relaxed);
-}
-
-void
-Clock::start(InvokeService & invoker)
-{
-    _running.store(true, std::memory_order_relaxed);
-    _invokeRegistration = invoker.registerInvoke([this]() { setTime(); });
-}
-
-void
-Clock::stop()
-{
-    _running.store(false, std::memory_order_relaxed);
-    _invokeRegistration.reset();
-}
-
 }
diff --git a/staging_vespalib/src/vespa/vespalib/util/clock.h b/staging_vespalib/src/vespa/vespalib/util/clock.h
index d4cffc200fe..0d160a98654 100644
--- a/staging_vespalib/src/vespa/vespalib/util/clock.h
+++ b/staging_vespalib/src/vespa/vespalib/util/clock.h
@@ -7,9 +7,6 @@
 
 namespace vespalib {
 
-class IDestructorCallback;
-class InvokeService;
-
 /**
  * Clock is a clock that updates the time at defined intervals.
  * It is intended used where you want to check the time with low cost, but where
@@ -19,28 +16,18 @@ class InvokeService;
 class Clock
 {
 private:
-    mutable std::atomic<int64_t>              _timeNS;
-    std::atomic<bool>                         _running;
-    std::unique_ptr<IDestructorCallback>      _invokeRegistration;
-
-    void setTime() const;
+    const std::atomic<steady_time>                 *_timeNS;
 public:
-    Clock();
+    Clock(const std::atomic<steady_time> * source) noexcept;
+    Clock(const Clock &) = delete;
+    Clock & operator =(const Clock &) = delete;
+    Clock(Clock &&) = delete;
+    Clock & operator =(Clock &&) = delete;
     ~Clock();
 
-    vespalib::steady_time getTimeNS() const {
-        if (!_running) {
-            setTime();
-        }
-        return getTimeNSAssumeRunning();
-    }
-    vespalib::steady_time getTimeNSAssumeRunning() const {
-        return vespalib::steady_time(std::chrono::nanoseconds(_timeNS.load(std::memory_order_relaxed)));
+    vespalib::steady_time getTimeNS() const noexcept {
+        return vespalib::steady_time(_timeNS->load(std::memory_order_relaxed));
     }
-
-    void start(InvokeService & invoker);
-    void stop();
 };
 
 }
-
diff --git a/staging_vespalib/src/vespa/vespalib/util/doom.h b/staging_vespalib/src/vespa/vespalib/util/doom.h
index b9a7e76b8af..e7db0795fb7 100644
--- a/staging_vespalib/src/vespa/vespalib/util/doom.h
+++ b/staging_vespalib/src/vespa/vespalib/util/doom.h
@@ -14,8 +14,8 @@ public:
     Doom(const Clock &clock, steady_time softDoom,
          steady_time hardDoom, bool explicitSoftDoom);
 
-    bool soft_doom() const { return (_clock.getTimeNSAssumeRunning() > _softDoom); }
-    bool hard_doom() const { return (_clock.getTimeNSAssumeRunning() > _hardDoom); }
+    bool soft_doom() const { return (_clock.getTimeNS() > _softDoom); }
+    bool hard_doom() const { return (_clock.getTimeNS() > _hardDoom); }
     duration soft_left() const { return _softDoom - _clock.getTimeNS(); }
     duration hard_left() const { return _hardDoom - _clock.getTimeNS(); }
     bool isExplicitSoftDoom() const { return _isExplicitSoftDoom; }
diff --git a/vespalib/src/tests/invokeservice/invokeservice_test.cpp b/vespalib/src/tests/invokeservice/invokeservice_test.cpp
index 1d4791f4a33..d56eb28e6c7 100644
--- a/vespalib/src/tests/invokeservice/invokeservice_test.cpp
+++ b/vespalib/src/tests/invokeservice/invokeservice_test.cpp
@@ -29,6 +29,25 @@ TEST("require that wakeup is called") {
     EXPECT_EQUAL(countAtStop, a._count);
 }
 
+TEST("require that now is moving forward") {
+    InvokeCounter a;
+    InvokeServiceImpl service(1ms);
+    EXPECT_EQUAL(0u, a._count);
+    steady_time prev = steady_clock::now();
+    auto ra = service.registerInvoke([&prev, &a, now=service.nowPtr() ]() noexcept {
+        EXPECT_GREATER(now->load(), prev);
+        prev = now->load();
+        a.inc();
+    });
+    EXPECT_TRUE(ra);
+    a.wait_for_atleast(100);
+    ra.reset();
+    EXPECT_GREATER_EQUAL(a._count, 100u);
+    steady_time now = steady_clock::now();
+    EXPECT_GREATER(now, prev);
+    EXPECT_LESS(now - prev, 5s);
+}
+
 TEST("require that same wakeup can be registered multiple times.") {
     InvokeCounter a;
     InvokeCounter b;
diff --git a/vespalib/src/vespa/vespalib/util/invokeservice.h b/vespalib/src/vespa/vespalib/util/invokeservice.h
index 3e3973234d1..22bee0d4526 100644
--- a/vespalib/src/vespa/vespalib/util/invokeservice.h
+++ b/vespalib/src/vespa/vespalib/util/invokeservice.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include "idestructorcallback.h"
+#include "time.h"
 #include <functional>
 
 namespace vespalib {
@@ -13,8 +14,9 @@ namespace vespalib {
  **/
 class InvokeService {
 public:
+    using InvokeFunc = std::function<void()>;
     virtual ~InvokeService() = default;
-    virtual std::unique_ptr<IDestructorCallback> registerInvoke(std::function<void()> func) = 0;
+    virtual std::unique_ptr<IDestructorCallback> registerInvoke(InvokeFunc func) = 0;
 };
 
 }
diff --git a/vespalib/src/vespa/vespalib/util/invokeserviceimpl.cpp b/vespalib/src/vespa/vespalib/util/invokeserviceimpl.cpp
index ffa0825c950..eac84568ec2 100644
--- a/vespalib/src/vespa/vespalib/util/invokeserviceimpl.cpp
+++ b/vespalib/src/vespa/vespalib/util/invokeserviceimpl.cpp
@@ -7,11 +7,12 @@ namespace vespalib {
 
 InvokeServiceImpl::InvokeServiceImpl(duration napTime)
     : _naptime(napTime),
+      _now(steady_clock::now()),
       _lock(),
       _currId(0),
       _closed(false),
       _toInvoke(),
-      _thread()
+      _thread(std::make_unique<std::thread>([this]() { runLoop(); }))
 {
 }
 
@@ -22,9 +23,7 @@ InvokeServiceImpl::~InvokeServiceImpl()
         assert(_toInvoke.empty());
         _closed = true;
     }
-    if (_thread) {
-        _thread->join();
-    }
+    _thread->join();
 }
 
 class InvokeServiceImpl::Registration : public IDestructorCallback {
@@ -44,20 +43,17 @@ private:
 };
 
 std::unique_ptr<IDestructorCallback>
-InvokeServiceImpl::registerInvoke(VoidFunc func) {
+InvokeServiceImpl::registerInvoke(InvokeFunc func) {
     std::lock_guard guard(_lock);
     uint64_t id = _currId++;
     _toInvoke.emplace_back(id, std::move(func));
-    if ( ! _thread) {
-        _thread = std::make_unique<std::thread>([this]() { runLoop(); });
-    }
     return std::make_unique<Registration>(this, id);
 }
 
 void
 InvokeServiceImpl::unregister(uint64_t id) {
     std::lock_guard guard(_lock);
-    auto found = std::find_if(_toInvoke.begin(), _toInvoke.end(), [id](const std::pair<uint64_t, VoidFunc> & a) {
+    auto found = std::find_if(_toInvoke.begin(), _toInvoke.end(), [id](const IdAndFunc & a) {
         return id == a.first;
     });
     assert (found != _toInvoke.end());
@@ -68,6 +64,8 @@ void
 InvokeServiceImpl::runLoop() {
     bool done = false;
     while ( ! done ) {
+        const steady_time now = steady_clock::now();
+        _now.store(now, std::memory_order_relaxed);
         {
             std::lock_guard guard(_lock);
             for (auto & func: _toInvoke) {
@@ -76,7 +74,7 @@ InvokeServiceImpl::runLoop() {
             done = _closed;
         }
         if ( ! done) {
-            std::this_thread::sleep_for(_naptime);
+            std::this_thread::sleep_until(now + _naptime);
         }
     }
 
diff --git a/vespalib/src/vespa/vespalib/util/invokeserviceimpl.h b/vespalib/src/vespa/vespalib/util/invokeserviceimpl.h
index 3b0c7690731..2448e381610 100644
--- a/vespalib/src/vespa/vespalib/util/invokeserviceimpl.h
+++ b/vespalib/src/vespa/vespalib/util/invokeserviceimpl.h
@@ -14,22 +14,24 @@ namespace vespalib {
  * An invoke service what will invoke the given function with at specified frequency.
  */
 class InvokeServiceImpl : public InvokeService {
-    using VoidFunc = std::function<void()>;
 public:
     InvokeServiceImpl(duration napTime);
     InvokeServiceImpl(const InvokeServiceImpl &) = delete;
     InvokeServiceImpl & operator=(const InvokeServiceImpl &) = delete;
     ~InvokeServiceImpl() override;
-    std::unique_ptr<IDestructorCallback> registerInvoke(VoidFunc func) override;
+    std::unique_ptr<IDestructorCallback> registerInvoke(InvokeFunc func) override;
+    const std::atomic<steady_time> * nowPtr() const { return &_now; }
 private:
+    using IdAndFunc = std::pair<uint64_t, InvokeFunc>;
     class Registration;
     void unregister(uint64_t id);
     void runLoop();
     duration                       _naptime;
+    std::atomic<steady_time>       _now;
     std::mutex                     _lock;
     uint64_t                       _currId;
     bool                           _closed;
-    std::vector<std::pair<uint64_t, VoidFunc>> _toInvoke;
+    std::vector<IdAndFunc>         _toInvoke;
     std::unique_ptr<std::thread>   _thread;
 };