* Rewrite complexity_test to use (hardcoded) manual time
This test is fundamentally flaky, because it tried to read tea leafs,
and is inherently misbehaving in CI environments,
since there are unmitigated sources of noise.
That being said, the computed Big-O also depends on the `--benchmark_min_time=`
Fixes https://github.com/google/benchmark/issues/272
* Correctly compute Big-O for manual timings. Fixes#1758.
* complexity_test: do more stuff in empty loop
* Make all empty loops be a bit longer empty
Looks like on windows, some of these tests still fail,
i guess clock precision is too small.
* State: Initialize counters with kAvgIteration in constructor
Previously, `counters` was updated in `PauseTiming()` with
`counters[name] += Counter(measurement, kAvgIteration)`.
The first `counters[name]` call inserts a counter with no flags.
There is no `operator+=` for `Counter`, so the insertion is done
by converting the `Counter` to a `double`, then constructing a
`Counter` to insert from the `double`, which drops the flags.
Pre-insert the `Counter` with the correct flags, then only
update `Counter::value`.
Introduced in 1c64a36 ([perf-counters] Fix pause/resume (#1643)).
* perf_counters_test.cc: Don't divide by iterations
Perf counters are now divided by iterations, so dividing again
in the test is wrong.
* State: Fix shadowed param error
* benchmark.cc: Fix clang-tidy error
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Co-authored-by: dominic <510002+dmah42@users.noreply.github.com>
* perf_counters_gtest: Make test pass on Android
Tested on Pixel 3 and Pixel 6. Reduce test to the intersection of
what passes on all platforms.
Pixel 6 doesn't support BRANCHES, and only supports two perf
counters.
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Co-authored-by: dominic <510002+dmah42@users.noreply.github.com>
* [perf-counters] Fix pause/resume
Using `state.PauseTiming() / state.ResumeTiming()` was broken.
Thanks [@virajbshah] for the the repro testcase.
* ran clang-format over the whole perf_counters_test.cc
* Remove check that perf counters are 0 on `Pause`, since `Pause`/`Resume`
sequences would cause a non-0 counter value
* both upper and lower bound for the with/without resume counters
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Co-authored-by: dominic <510002+dmah42@users.noreply.github.com>
* Add pfm CI actions for bazel
* Fix problems in unit test.
* Undo enabling the CI tests for pfm - github CI machines seemingly do not support performance counters.
* Remove commented code - can be revisited in github history when needed, and there's a comment explaining the rationale behind the new test code.
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Co-authored-by: Andy Christiansen <achristiansen@google.com>
Co-authored-by: dominic <510002+dmah42@users.noreply.github.com>
* Support optional, user-directed collection of performance counters
The patch allows an engineer wishing to drill into the root causes
of a regression, for example. Currently, only single threaded runs
are supported. The feature is a build-time opt in, and then a runtime
opt in.
The engineer may run the benchmark executable, passing a list of
performance counter names (using libpfm's naming scheme) at the
command line. The counter values will then be collected and reported
back as UserCounters.
This is different from #240 in that it is a benchmark user opt-in, and
the counter collection is transparent to the benchmark.
Currently, this is only supported on platforms where libpfm is
supported.
libpfm: http://perfmon2.sourceforge.net/
* 'Use' values param in Snapshot when BENCHMARK_OS_WINDOWS
This is to avoid unused parameter warning-as-error
* Added missing include for <vector> in perf_counters.cc
* Moved doc to docs
* Added license blurbs
Roman Lebedev