linux-kernel - Re: big picture UDP/IP performance question re 2.6.18 -> 2.6.32

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-next>] [day] [month] [year] [list]

Message-Id: <6.2.5.6.2.20111005025227.03a9d9f0@binnacle.cx>
Date:	Wed, 05 Oct 2011 02:58:17 -0400
From:	starlight@...nacle.cx
To:	Joe Perches <joe@...ches.com>, Christoph Lameter <cl@...two.org>,
	Serge Belyshev <belyshev@...ni.sinp.msu.ru>,
	Con Kolivas <kernel@...ivas.org>
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	linux-kernel@...r.kernel.org, netdev <netdev@...r.kernel.org>,
	Willy Tarreau <w@....eu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Stephen Hemminger <stephen.hemminger@...tta.com>
Subject: Re: big picture UDP/IP performance question re 2.6.18
  -> 2.6.32

Final note:

I had captured latency measurements for
two of the three kernels.  Just ran
2.6.18(rhel5) and the results are
stunning.  The older kernel is much,
much better then the newer kernel.

Average latency is three times better
and the standard deviation is six
time better.  As in 300% and 600%.

Latency here is the time it takes
a packet to travel from the kernel
(where it is timestamped) till it
reaches the final consumption point
in the application.

Makes me think that the old kernel
is better at keeping caches hot and
scheduling woken threads on the same
cores as the threads that triggered
them.

--
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/