lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <1357232977.1886.17.camel@mesosphere.localdomain> Date: Fri, 04 Jan 2013 00:09:37 +0700 From: Roman Dubtsov <dubtsov@...il.com> To: Michel Lespinasse <walken@...gle.com> Cc: linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...capital.net>, Rik van Riel <riel@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, Hugh Dickins <hughd@...gle.com> Subject: Re: mmap() scalability in the presence of the MAP_POPULATE flag On Wed, 2013-01-02 at 16:09 -0800, Michel Lespinasse wrote: > > Is there an interest in fixing this or concurrent mmaps() from the same > > process are too much of a corner case to worry about it? > > Funny this comes up again. I actually have a patch series that is > supposed to do that: > [PATCH 0/9] Avoid populating unbounded num of ptes with mmap_sem held > > However, the patches are still pending, didn't get much review > (probably not enough for Andrew to take them at this point), and I > think everyone forgot about them during the winter break. > > Care to have a look at that thread and see if it works for you ? > > (caveat: you will possibly also need "[PATCH 10/9] mm: make > do_mmap_pgoff return populate as a size in bytes, not as a bool" to > make the series actually work for you) I applied the patches on top of 3.7.1. Here're the results for 4 threads concurrently mmap()-ing 10 64MB buffers in a loop without munmap()-s. The data is from a Nehalem i7-920 single-socket 4-core CPU. I've also added the older data I have for the 3.6.11 (patched and not) for reference. 3.6.11 vanilla, do not populate: 0.001 seconds 3.6.11 vanilla, populate via a loop: 0.216 seconds 3.6.11 vanilla, populate via MAP_POPULATE: 0.358 seconds 3.6.11 + crude patch, do not populate: 0.002 seconds 3.6.11 + crude patch, populate via loop: 0.215 seconds 3.6.11 + crude patch, populate via MAP_POPULATE: 0.217 seconds 3.7.1 vanilla, do not populate: 0.001 seconds 3.7.1 vanilla, populate via a loop: 0.216 seconds 3.7.1 vanilla, populate via MAP_POPULATE: 0.411 seconds 3.7.1 + patch series, do not populate: 0.001 seconds 3.7.1 + patch series, populate via loop: 0.216 seconds 3.7.1 + patch series, populate via MAP_POPULATE: 0.273 seconds So, the patch series mentioned above do improve performance but as far as I can read the benchmarking data there's still some performance left on the table. Regards, Roma -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists