RFR: 8317453: NMT: Performance benchmarks are needed to measure speed and memory [v10]

[Gerard Ziemski]

On Mon, 5 May 2025 13:06:37 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Gerard Ziemski has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   use permit_forbidden_function for realloc
>
> src/hotspot/share/nmt/memLogRecorder.hpp line 136:
> 
>> 134:     address stack[NMT_TrackingStackDepth];
>> 135:     long int mem_tag;
>> 136:     long int mem_tag_split;
> 
> Use MemTag? Why `long int`?

I think I was more comfortable with explicit types, since they are the struct that gets written to the disk, I wanted to know exactly how they are going to be laid out on a disk to make it easier to parse the data while debugging.

Can this stay as is?

> src/hotspot/share/nmt/memLogRecorder.hpp line 139:
> 
>> 137:     size_t size;
>> 138:     size_t size_split;
>> 139:     int type;
> 
> Why isn't this a `Type`?

Same answer as above.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23786#discussion_r2077914949
PR Review Comment: https://git.openjdk.org/jdk/pull/23786#discussion_r2077915542