Revise perfjitdump #229
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Revise perfjitdump #229
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Remove unnecessary fsync() call Use writev() instead of write() to reduce OS calls Handle partial write cases
sdmaclea
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lpereira
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Thanks @lpereira |
janvorli
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| @@ -136,7 +136,7 @@ struct PerfJitDumpState | |||
| codeIndex(0) | |||
| {} | |||
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| bool enabled; | |||
| volatile bool enabled; | |||
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Use of volatile in C++ always make me uneasy that it's actually hiding something else. I haven't read the code for PerfJitDumpState yet, but what's the reason to qualify enabled as volatile here?
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It is a variable that is expected to be written by another thread during Finish.
Before we lock the mutex, we read enabled. After locking I want to make sure enabled is read again in case Finish disabled it. I marked it as volatile to prevent the optimizer from using the value it had initially read. Given that the locking is a function call it might not be needed, but I don't fully understand the nuances of the C++ optimization rules.
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Remove unnecessary fsync() call
Use writev() instead of write() to reduce OS calls
Handle partial write cases
Fixes dotnet/coreclr#27912 (aka #13812)