Merge pull request #21266 from vespa-engine/balder/add-method-to-get-default-timer-frequency

Add a base vespa timer frequency that is used as a base to control po…

3 files changed, 27 insertions, 0 deletions

diff --git a/vespalib/src/tests/time/time_test.cpp b/vespalib/src/tests/time/time_test.cpp
index 0bef18ddc0d..c2858308006 100644
--- a/vespalib/src/tests/time/time_test.cpp
+++ b/vespalib/src/tests/time/time_test.cpp
@@ -64,4 +64,8 @@ TEST(TimeTest, conversion_of_max) {
     EXPECT_EQ(9223372036.8547764, vespalib::to_s(vespalib::duration::max()));
 }
 
+TEST(TimeTest, default_timer_frequency_is_1000_hz) {
+    EXPECT_EQ(1000u, getVespaTimerHz());
+}
+
 GTEST_MAIN_RUN_ALL_TESTS()
diff --git a/vespalib/src/vespa/vespalib/util/time.cpp b/vespalib/src/vespa/vespalib/util/time.cpp
index b5c019b4a27..bcc289489ea 100644
--- a/vespalib/src/vespa/vespalib/util/time.cpp
+++ b/vespalib/src/vespa/vespalib/util/time.cpp
@@ -3,6 +3,9 @@
 #include "time.h"
 #include <thread>
 
+#include <vespa/log/log.h>
+
+LOG_SETUP(".vespalib.time");
 namespace vespalib {
 
 system_time
@@ -12,6 +15,21 @@ to_utc(steady_time ts) {
     return system_time(std::chrono::duration_cast<system_time::duration>(nowUtc.time_since_epoch() - nowSteady.time_since_epoch() + ts.time_since_epoch()));
 }
 
+uint32_t
+getVespaTimerHz() {
+    const char * vespa_timer_hz = getenv("VESPA_TIMER_HZ");
+    if (vespa_timer_hz != nullptr) {
+        try {
+            size_t idx(0);
+            uint32_t tmp = std::stoi(vespa_timer_hz, &idx, 0);
+            return std::max(1u, std::min(1000u, tmp));
+        } catch (const std::exception & e) {
+            LOG(warning, "Parsing environment VESPA_TIMER_HZ='%s' failed with exception: %s", vespa_timer_hz, e.what());
+        }
+    }
+    return 1000u;
+}
+
 namespace {
 
 string
diff --git a/vespalib/src/vespa/vespalib/util/time.h b/vespalib/src/vespa/vespalib/util/time.h
index f19d71afb32..dbbae862a8d 100644
--- a/vespalib/src/vespa/vespalib/util/time.h
+++ b/vespalib/src/vespa/vespalib/util/time.h
@@ -88,4 +88,9 @@ public:
     static void waitAtLeast(duration dur, bool busyWait);
 };
 
+/**
+ * The default frequency (1000hz) for vespa timer, with environment override VESPA_TIMER_HZ capped to [1..1000]
+ */
+uint32_t getVespaTimerHz();
+
 }