[PATCH] D146301: [llvm-exegesis] Make possible to execute snippets without perf counters

[Clement Courbet via Phabricator via llvm-commits]

courbet added a comment.

Thanks. In principle that sounds goods, my only real remark is about what flags we use to communicate that intent to the tool.



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Comment at: llvm/tools/llvm-exegesis/lib/PerfHelper.cpp:129
               "space perf monitoring.\nYou may want to try:\n$ sudo sh "
               "-c 'echo -1 > /proc/sys/kernel/perf_event_paranoid'\n";
   }
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I think you can add something about not using actual perf counters if that's waht the user wants:

"If you are debugging and you don't want to actually read performance counters, use `--use-dummy-perf-events`


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Comment at: llvm/tools/llvm-exegesis/llvm-exegesis.cpp:137-140
+        clEnumValN(exegesis::BenchmarkPhaseSelectorE::ExecuteWithDummyCounters,
+                   "execute-with-dummy-counters",
+                   "Same as prepare-measured-code, but also runs the snippet "
+                   "(without real measurement - for testing only!)"),
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I think this should be its own separate flag. This is only really used in `main` to parameterize how to measure, but we're still "measuring" stuff.


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https://reviews.llvm.org/D146301