This patch adds support for validation counters. Validation counters can
be used to measure events that occur during snippet execution like cache
misses to ensure that certain assumed invariants about the benchmark
actually hold. Validation counters are setup within a perf event group,
so are turned on and off at exactly the same time as the "group leader"
counter that measures the desired value.
This completes the FIXME listed in FunctionExecutor in regards to
deprecating this function. It simply makes the appropriate call into
runAndSample and grabs the first counter value. This patch completely
removes the function, moving that logic into the callers (currently only
uopsBenchmarkRunner). This makes creating new FunctionExecutors easier
as an implementation no longer needs to worry about this detail.
Reviewed By: gchatelet
Differential Revision: https://reviews.llvm.org/D147878
The addition of `inverse_throughput` mode highlighted the disjointedness
of snippet generators and benchmark runners because it used the
`UopsSnippetGenerator` with the `LatencyBenchmarkRunner`.
To keep the code consistent tie the snippet generators to
parallelization/serialization rather than their benchmark runners.
Renaming `LatencySnippetGenerator` -> `SerialSnippetGenerator`.
Renaming `UopsSnippetGenerator` -> `ParallelSnippetGenerator`.
Differential Revision: https://reviews.llvm.org/D72928
