* 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
* Add missing <cerrno> header
This commit fixes a current build error on Android where 'errno' is an unidentified
symbol due to a missing header
* Update string_util.cc
Conditionally adds <cerrno> if BENCHMARK_STL_ANDROID_GNUSTL is defined
* escape special chars in csv and json output.
- escape \b,\f,\n,\r,\t,\," from strings before dumping
them to json or csv.
- also faithfully reproduce the sign of nan in json.
this fixes github issue #745.
* functionalize.
* split string escape functions between csv and json
* Update src/csv_reporter.cc
Co-Authored-By: tesch1 <tesch1@gmail.com>
* Update src/json_reporter.cc
Co-Authored-By: tesch1 <tesch1@gmail.com>
* Fix compilation on Android with GNU STL
GNU STL in Android NDK lacks string conversion functions from C++11, including std::stoul, std::stoi, and std::stod.
This patch reimplements these functions in benchmark:: namespace using C-style equivalents from C++03.
* Avoid use of log2 which doesn't exist in Android GNU STL
GNU STL in Android NDK lacks log2 function from C99/C++11.
This patch replaces their use in the code with double log(double) function.
* Rename StringXxx to StrXxx in string_util.h and its users
This makes the naming consistent within string_util and moves is the
Abseil convention.
* Style guide is 2 spaces before end of line "//" comments
* Rename StrPrintF/StringPrintF to StrFormat for absl compatibility.
When generating a human-readable number for user counters, we don't
generally expect 1k to be 1024. This is the default due to the more
general purpose string utility.
Fixes#437
This patch adopts a new internal structure for how timings are performed.
Currently every iteration of a benchmark checks to see if it has been running
for an appropriate amount of time. Checking the clock introduces noise into
the timings and this can cause inconsistent output from each benchmark.
Now every iteration of a benchmark only checks an iteration count to see if it
should stop running. The iteration count is determined before hand by testing
the benchmark on a series of increasing iteration counts until a suitable count
is found. This increases the amount of time it takes to run the actual benchmarks
but it also greatly increases the accuracy of the results.
This patch introduces some breaking changes. The notable breaking changes are:
1. Benchmarks run on multiple threads no generate a report per thread. Instead
only a single report is generated.
2. ::benchmark::UseRealTime() was removed and replaced with State::UseRealTime().
