linux-kernel - Re: cpufreq affects traffic control rates

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] [day] [month] [year] [list]

Message-ID: <20070829102005.5450723e@freepuppy.rosehill.hemminger.net>
Date:	Wed, 29 Aug 2007 10:20:05 -0700
From:	Stephen Hemminger <shemminger@...ux-foundation.org>
To:	Jan Engelhardt <jengelh@...putergmbh.de>
Cc:	DervishD <lkml@...vishd.net>,
	Linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: cpufreq affects traffic control rates

On Wed, 29 Aug 2007 17:26:24 +0200 (CEST)
Jan Engelhardt <jengelh@...putergmbh.de> wrote:

> 
> On Aug 28 2007 15:23, Stephen Hemminger wrote:
> >>     I noticed lately that my traffic control rates were being very slow,
> >> about 40% less than expected, and finally spotted the problem: cpufreq.
> >> 
> >>     Looks like HTB puts buckets according to the requested rate but
> >> assuming that the CPU is running at its default clock or something like
> >> that.
> >> 
> >Is the problem configuration of network scheduler clock? In 2.6.20 and earlier, you
> >could use CPU cycle counter (later kernels only use time of day).  So try
> >switching to jiffies or gettimeofday.
> 
> This should not have been removed. CPUs with constant_tsc
> could still be used with "CPU cycle counter" method.
> 
> 
> 	Jan

It was removed because the core clock subsystem now manages the choice
of CPU clock correctly and should provide the highest resolution possible
on the hardware.

Plus a whole bunch of grotty macro code gets removed. And the math
handling was more standard/simpler.

-- 
Stephen Hemminger <shemminger@...ux-foundation.org>
-
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/