When running benchmarks, the user may choose to request collection of performance counters. This may be useful in investigation scenarios - narrowing down the cause of a regression; or verifying that the underlying cause of a performance improvement matches expectations.
This feature is available if:
The feature does not require modifying benchmark code. Counter collection is handled at the boundaries where timer collection is also handled.
apt-get install libpfm4-dev.
To use, pass a comma-separated list of counter names through the
--benchmark_perf_counters flag. The names are decoded through libpfm - meaning, they are platform specific, but some (e.g.
INSTRUCTIONS) are mapped by libpfm to platform-specifics - see libpfm documentation for more details.
The counter values are reported back through the User Counters mechanism, meaning, they are available in all the formats (e.g. JSON) supported by User Counters.