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
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <ZV6oYmVYsyYizvgg@archie.me>
Date:   Thu, 23 Nov 2023 08:18:26 +0700
From:   Bagas Sanjaya <bagasdotme@...il.com>
To:     Chun Ng <chunn@...dia.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:     Linux Regressions <regressions@...ts.linux.dev>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux Memory Management List <linux-mm@...ck.org>,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>,
        Ankita Garg <ankitag@...dia.com>
Subject: Re: [REGRESSION]: mmap performance regression starting with k-6.1

On Wed, Nov 22, 2023 at 08:03:19PM +0000, Chun Ng wrote:
> Hi,
> 
> Recently I observed there is performance regression on system call mmap(..). I tried both vanilla kernels and Raspberry Pi kernels on a Raspberry Pi 4 box and the results are pretty consistent among them.
> 
> Bisection showed that the regression starts from k-6.1, and the latest vanilla k-6.7 is still showing the same regression.
> 
> The test program calls mmap/munmap for a 4K page with MAP_ANON and MAP_PRIVATE flags, and ftrace is used to measure the time spent on the do_mmap(..) call.  Measured time of a sample run with different vanilla kernel versions are:
> k-5.10 and k-6.0: ~157us
> k-6.1: ~194us
> k-6.7: ~214us
> Results are pretty consistent across multiple runs with a small percentage variance.  Ftrace shows that latency of mmap_region(...) has increased since k-6.1.  An application that makes frequent mmap(..) calls the accumulated extra latency is very noticeable. 

Did you mean that v6.0 doesn't have this regression?

Confused...

-- 
An old man doll... just what I always wanted! - Clara

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ