RE: [EXTERNAL] Re: [PATCH v4] perf inject --jit: Remove //anon mmap events

[Steve MacLean]

>/tmp/perf/perf record -k 1 -e cycles:u -o /tmp/perf.data java 
>-agentpath:/tmp/perf/libperf-jvmti.so -XX:+PreserveFramePointer 
>-XX:InitialCodeCacheSize=20M -XX:ReservedCodeCacheSize=1G -jar 
>dacapo-9.12-bach.jar jython 

Its also possible the `InitialCodeCacheSize=20M` argument is masking the problem.  Something like 4K would make the problem much easier to see.

I see the problem every time .NET grows the cache across a 64K page boundary.  20M may mean you are allocating huge pages or something which might mask the problem. We may be allocating code pages 64K at a time.