Messages in this thread | | | Subject | Re: [PATCH/RFC] mm: add and use batched version of __tlb_remove_table() | From | Nikita Yushchenko <> | Date | Thu, 23 Dec 2021 12:55:38 +0300 |
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>> I currently don't have numbers for this patch taken alone. This patch >> originates from work done some years ago to reduce cost of memory >> accounting, and x86-only version of this patch was in virtuozzo/openvz >> kernel since then. Other patches from that work have been upstreamed, >> but this one was missed. >> >> Still it's obvious that release_pages() shall be faster that a loop >> calling put_page() - isn't that exactly the reason why release_pages() >> exists and is different from a loop calling put_page()? > > Yep, but this patch does a bunch of stuff to some really hot paths. It > would be greatly appreciated if you could put in the effort to actually > put some numbers behind this. Plenty of weird stuff happens on > computers that we suck at predicting.
I found the original report about high cost of memory accounting, and tried to repeat the test described there, with and without the patch.
The test is - run a script in 30 openvz containers in parallel, and measure average time per execution. Script is attached.
I'm getting measurable improvement in average msecs per execution: 15360 ms without patch, 15170 ms with patch. And this difference is reliably reproducible.
Nikita [unhandled content-type:application/x-sh] | |