netdev - Re: [PATCH 0/2] HTB scheduler HTB

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Date:	Thu, 12 Jun 2008 12:01:15 +0200
From:	Jesper Dangaard Brouer <jdb@...x.dk>
To:	Martin Devera <devik@....cz>
Cc:	"David S. Miller" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Patrick McHardy <kaber@...sh.net>
Subject: Re: [PATCH 0/2] HTB scheduler HTB_HYSTERESIS modifications

On Wed, 2008-06-04 at 16:28 +0200, Jesper Dangaard Brouer wrote:
> Okay, lets wait until I get this kernel into our real-life production
> system.  Then I can report on the real-life impact on CPU performance.

I have now tested/deployed the patches on two production servers.

 Conclusion is: It should be safe to apply these patches.

See full report here:
http://people.netfilter.org/hawk/patches/htb_nohyst/production_test_results.html

We saw an increased number of interrupts on the test system, when
enabling/disabling htb_hysteresis.

 This didn't show up on the production system.

I believe that the increased intr (on test system) is an artifact of the
TCP download got less bursty and more smooth.

I could not measure any increased CPU usage when enabling/disabling
htb_hysteresis.

P.S. As a side note: 
 Network performance on 2.6.24.4 seems very good! Surprisingly the CPU
usage decreased significanly (see images in full report), when upgrading
to kernel 2.6.25.4 (from 2.6.15). I have not Oprofiled, but from
previous experiences, I believe that its primarily caused by Patrick
McHardys RCU patches to netfilter conntrack, Thanks Patrick!!! :-)

-- 
Med venlig hilsen / Best regards
  Jesper Brouer
  ComX Networks A/S
  Linux Network developer
  Cand. Scient Datalog / MSc.
  Author of http://adsl-optimizer.dk
  LinkedIn: http://www.linkedin.com/in/brouer

View attachment "production_test_results.txt" of type "text/plain" (2963 bytes)