RFR: 8333994: NMT: call stacks should show source information [v2]

[Gerard Ziemski]

On Mon, 17 Jun 2024 15:25:33 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> > I have the same question. Did dwarf decoder performance improve? If so, could you point me the PR? Thanks!
> 
> I completely forgot that this had been an issue. The comment was even written by me :(
> 
> No, Elf decoder is still slow. But I have found myself too many times staring at NMT output now trying to make sense of the offsets. Missing source info in combination with the small stack size of 4 makes investigations a pain.
> 
> I added a simple caching mechanism to aid printing. Its pretty straight-forward, but still I am not sure it is worth the complexity. Here the numbers:
> 
> Running all NMT jtreg tests:
> 
> * Stock JVM (no source info): 40 seconds
> * Source info: 2 min 30 seconds
> * Source info + caching: 1 min 15 seconds
> 
> I think that is acceptable. Any more intricate caching would be over the complexity-benefit line.

I simply pointed out your own old concern. If you are happy with the final performance now, then I'm good.

I will look at the cache shortly.

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PR Comment: https://git.openjdk.org/jdk/pull/19655#issuecomment-2176934980