RFR: CODETOOLS-7902799: perfasm still handles event modifiers incorrectly [v2]

[Aleksey Shipilev]

On Tue, 8 Dec 2020 09:18:41 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> No, no problem. I was just unsure what it means that you've self-assigned this to you. Apparently it means that you'll take care :)
>> 
>> Thanks for the quick response.
>
> Unfortunately, this regresses `perfasm` on systems that reply `cycles:u:` in default configuration:
> 
> 21831844.118759: cycles:u:  ffff000010081478 [unknown] ([unknown])
> 
> ...yields:
> 
> PrintAssembly processed: 202041 total address lines.
> Perf output processed (skipped 12.981 seconds):
>  Column 1: cycles (0 events)

What's worse, if I do:

$ java -jar benchmarks.jar JMHSample_09_Blackholes.measureRight_2 -f 1 -w 1s -r 1s -prof "perfasm:savePerf=true;events=cycles:ppp

...
Perf output processed (skipped 13.276 seconds):
 Column 1: cycles:ppp (0 events)

$ head ./org.openjdk.jmh.samples.JMHSample_09_Blackholes.measureRight_2-AverageTime.perf
21832047.816581: cycles:pppu:      ffffa34b1080 _start (/usr/lib64/ld-2.28.so)

So perf liberally adds `u` to the event tags. I guess we should go back at fixing the parsing code to match events without tags?

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PR: https://git.openjdk.java.net/jmh/pull/9