netdev - Re: cat /proc/net/tcp takes 0.5 seconds on x86

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: <20080827214700.GB26610@one.firstfloor.org>
Date:	Wed, 27 Aug 2008 23:47:00 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Trent Piepho <tpiepho@...escale.com>
Cc:	Andi Kleen <andi@...stfloor.org>, Dave Jones <davej@...hat.com>,
	netdev@...r.kernel.org, j.w.r.degoede@....nl
Subject: Re: cat /proc/net/tcp takes 0.5 seconds on x86_64

On Wed, Aug 27, 2008 at 02:29:18PM -0700, Trent Piepho wrote:
> On Wed, 27 Aug 2008, Andi Kleen wrote:
> > On a 2GB Core2 system here I see a time cat /proc/net/tcp > /dev/null
> > constently dropping from 0.44s to 0.4-0.8s system time with this change.
> > This is with mostly empty hash tables.
> 
> Umm, 0.4 to 0.8 seconds is on average _slower_ than 0.44 seconds.  Did you
> mean .04 to .08?

Yes noticed that too -- i think it must have been .04-.08 and the zeros
got lost somewhere. I remember that it was significantly faster. It's really 
a benchmark how fast an read lock aquire/release is, but even on 
the best systems it's quite slow compared to lockless code.

-Andi

-- 
ak@...ux.intel.com
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html