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From: Andi Kleen <ak@muc.de>
To: Greg Banks <gnb@sgi.com>
Cc: Arthur Kepner <akepner@sgi.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
	netdev@oss.sgi.com, davem@redhat.com
Subject: Re: NAPI, e100, and system performance problem
Date: Fri, 22 Apr 2005 13:36:56 +0200	[thread overview]
Message-ID: <m1hdhzyrdz.fsf@muc.de> (raw)
In-Reply-To: <20050419055535.GA12211@sgi.com> (Greg Banks's message of "Tue, 19 Apr 2005 15:55:35 +1000")

Greg Banks <gnb@sgi.com> writes:
>
> An inordinate amount of CPU is being spent running around polling the
> device instead of dealing with the packets in IP, TCP and NFS land.
> By inordinate, we mean twice as much or more cpu% than a MIPS/Irix
> box with slower CPUs.

We have seen similar behaviour. With NAPI some benchmarks run
a lot slower than on a driver on the same hardware/NIC without NAPI.
This can be even observed with simple tests like netperf single stream
between two boxes.

There seems to be also some problems with bidirectional traffic, although
I have not fully tracked them down to NAPI yet.

There is definitely some problem in NAPI land ...

-Andi

  parent reply	other threads:[~2005-04-22 11:36 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-18  6:11 NAPI, e100, and system performance problem Brandeburg, Jesse
2005-04-18 12:14 ` jamal
2005-04-18 15:36 ` Robert Olsson
2005-04-18 16:55 ` Arthur Kepner
2005-04-18 19:34   ` Robert Olsson
2005-04-18 20:26   ` jamal
2005-04-19  5:55     ` Greg Banks
2005-04-19 18:36       ` David S. Miller
2005-04-19 20:38         ` NAPI and CPU utilization [was: NAPI, e100, and system performance problem] Arthur Kepner
2005-04-19 20:52           ` Rick Jones
2005-04-19 21:09           ` David S. Miller
     [not found]         ` <20050420145629.GH19415@sgi.com>
2005-04-20 15:15           ` NAPI, e100, and system performance problem jamal
2005-04-22 11:36       ` Andi Kleen [this message]
2005-04-22 12:33         ` jamal
2005-04-22 17:21           ` Andi Kleen
2005-04-22 18:18             ` jamal
2005-04-22 18:30               ` Andi Kleen
2005-04-22 18:37                 ` Arthur Kepner
2005-04-22 18:52                   ` David S. Miller
     [not found]                     ` <Pine.LNX.4.61.0504241845070.2934@linux.site>
2005-04-25 11:25                       ` jamal
2005-04-25 18:51                         ` David S. Miller
2005-04-25 11:41                       ` jamal
2005-04-25 12:16                         ` Jamal Hadi Salim
2005-04-22 19:01                 ` jamal
2005-04-22 19:07                   ` David S. Miller
2005-04-22 19:21                     ` jamal
2005-04-23 20:50                       ` Robert Olsson
2005-04-23 16:56                 ` Robert Olsson
2005-04-22 23:28               ` Greg Banks
2005-04-22 23:40                 ` Stephen Hemminger
2005-04-22 23:43                   ` David S. Miller
2005-04-23  2:51                     ` Stephen Hemminger
2005-04-23 17:54                       ` Robert Olsson
2005-04-23  3:04                     ` jamal
2005-04-23 17:14                     ` Robert Olsson
2005-04-22 14:52         ` Robert Olsson
2005-04-22 15:37           ` jamal
2005-04-22 17:22             ` Andi Kleen

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