Messages in this thread | | | Date | Tue, 30 May 2023 00:59:30 -0700 | From | Andi Kleen <> | Subject | Re: [PATCH v2 00/16] Address some perf memory/data size issues |
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> BSS won't count toward file size, which the patches were primarily > going after - but checking the size numbers I have miscalculated from > reading size's output that I'm not familiar with. The numbers are > still improved, but I just see a 37kb saving, with 5kb more in > .rodata. Something but not much. .data.rel.ro is larger, which imo is > good, but those pages will still be dirtied so a mute point wrt file > size and memory overhead.
The way perf is written (lots of separate code depending on a single high level switch) most pages probably won't be dirtied.
> > For huge pages I thought it was correct that things are aligned by max > page size which I thought on x86-64 was 2MB, so I tried: > EXTRA_LDFLAGS="-z max-page-size=4096" > but it made no difference to anything, and with: > EXTRA_CFLAGS="-Wl,-z,max-page-size=4096" > EXTRA_CXXFLAGS="-Wl,-z,max-page-size=4096" > file size just got worse.
The default alignment to 2MB was dropped in the GNU toolchain in 2018 or so.
-Andi
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