From eef2bd2d629588fea48d23d4d8b481b83ce6d231 Mon Sep 17 00:00:00 2001
From: Henning Baldersheim <balder@yahoo-inc.com>
Date: Fri, 22 Nov 2019 12:56:54 +0000
Subject: Add a benchmark for the clock

---
 staging_vespalib/src/tests/clock/.gitignore        |  1 +
 staging_vespalib/src/tests/clock/CMakeLists.txt    |  6 +++
 .../src/tests/clock/clock_benchmark.cpp            | 53 ++++++++++++++++++++++
 staging_vespalib/src/tests/clock/clock_test.cpp    |  2 +-
 4 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 staging_vespalib/src/tests/clock/clock_benchmark.cpp

(limited to 'staging_vespalib')

diff --git a/staging_vespalib/src/tests/clock/.gitignore b/staging_vespalib/src/tests/clock/.gitignore
index 1826ba1563b..b0fcd343176 100644
--- a/staging_vespalib/src/tests/clock/.gitignore
+++ b/staging_vespalib/src/tests/clock/.gitignore
@@ -2,3 +2,4 @@
 Makefile
 clock_test
 staging_vespalib_clock_test_app
+staging_vespalib_clock_benchmark_app
diff --git a/staging_vespalib/src/tests/clock/CMakeLists.txt b/staging_vespalib/src/tests/clock/CMakeLists.txt
index e62ef47e18a..825c0ae36cb 100644
--- a/staging_vespalib/src/tests/clock/CMakeLists.txt
+++ b/staging_vespalib/src/tests/clock/CMakeLists.txt
@@ -1,4 +1,10 @@
 # Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+vespa_add_executable(staging_vespalib_clock_benchmark_app TEST
+    SOURCES
+    clock_benchmark.cpp
+    DEPENDS
+    staging_vespalib
+)
 vespa_add_executable(staging_vespalib_clock_test_app TEST
     SOURCES
     clock_test.cpp
diff --git a/staging_vespalib/src/tests/clock/clock_benchmark.cpp b/staging_vespalib/src/tests/clock/clock_benchmark.cpp
new file mode 100644
index 00000000000..49eac95de66
--- /dev/null
+++ b/staging_vespalib/src/tests/clock/clock_benchmark.cpp
@@ -0,0 +1,53 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/vespalib/util/clock.h>
+#include <cassert>
+#include <vector>
+
+using vespalib::Clock;
+using fastos::TimeStamp;
+
+struct Sampler : public FastOS_Runnable {
+    Sampler(Clock & clock, fastos::SteadyTimeStamp end) :
+       _samples(0),
+       _clock(clock),
+       _theEnd(end)
+   { }
+    void Run(FastOS_ThreadInterface *, void *) override {
+        printf("Starting at %s with doom at %s\n", _clock.getTimeNSAssumeRunning().toString().c_str(), _theEnd.toString().c_str());
+        for (_samples = 0; (_clock.getTimeNSAssumeRunning() < _theEnd) && (_samples < 40000000000l); _samples++) {
+
+        }
+        printf("Took %ld clock samples at %s\n", _samples, _clock.getTimeNSAssumeRunning().toString().c_str());
+    }
+    uint64_t _samples;
+    const Clock & _clock;
+    fastos::SteadyTimeStamp _theEnd;
+    FastOS_ThreadInterface * _thread;
+};
+void sample() {
+
+}
+
+int
+main(int , char *argv[])
+{
+    long frequency = atoll(argv[1]);
+    int numThreads = atoi(argv[2]);
+    Clock clock(1.0/frequency);
+    FastOS_ThreadPool pool(0x10000);
+    assert(pool.NewThread(&clock, nullptr) != nullptr);
+
+    std::vector<std::unique_ptr<Sampler>> threads;
+    threads.reserve(numThreads);
+    for (int i(0); i < numThreads; i++) {
+        threads.push_back(std::make_unique<Sampler>(clock, fastos::ClockSteady::now() + 10*TimeStamp::SEC));
+        Sampler * sampler = threads[i].get();
+        sampler->_thread = pool.NewThread(threads[i].get(), nullptr);
+    }
+    for (const auto & sampler : threads) {
+        sampler->_thread->Join();
+    }
+    pool.Close();
+    clock.stop();
+}
diff --git a/staging_vespalib/src/tests/clock/clock_test.cpp b/staging_vespalib/src/tests/clock/clock_test.cpp
index 45f17bbba92..c8c93272e85 100644
--- a/staging_vespalib/src/tests/clock/clock_test.cpp
+++ b/staging_vespalib/src/tests/clock/clock_test.cpp
@@ -20,7 +20,7 @@ Test::Main()
 
     Clock clock(0.050);
     FastOS_ThreadPool pool(0x10000);
-    ASSERT_TRUE(pool.NewThread(&clock, NULL) != NULL);
+    ASSERT_TRUE(pool.NewThread(&clock, nullptr) != nullptr);
     fastos::SteadyTimeStamp start = clock.getTimeNS();
     FastOS_Thread::Sleep(5000);
     fastos::SteadyTimeStamp stop = clock.getTimeNS();
-- 
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