Capture critical PMCs for perf and render flamegraph using these

[ambud]

Currently we are only capturing default perf for perf based profiling, it doesn't capture any other types of events. This issue is created to request we that we allow ability for dynamic profiler to invoke perf with specific events and build a flamegraph for these to aid in solving and tracing performance issues.

To start with we want:

• cache-misses
• stalled-frontend / backend

[mlim19]

@ambud, can you elaborate this request? I think the perfspect tool can provides such metrics already or can extend if not there. Do you want to build a different flamegraph or attribute them to the existing flamegraph?

[prashantbytesyntax]

@mlim19 to clarify this requirement
support profiling based on pmu events like (cache-misses, stalled-cycles-frontend/backend etc. right ? since today perf in gprofiler only support timer based events ( pmu cycles for sampling OR software timer as fallback). So the output visualization is still flamegraph here and NOT perfspect