From: linas@austin.ibm.com (Linas Vepstas)
To: Jan-Bernd Themann <ossthema@de.ibm.com>
Cc: Thomas Klein <tklein@de.ibm.com>,
Jan-Bernd Themann <themann@de.ibm.com>,
netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-ppc <linuxppc-dev@ozlabs.org>, Bodo Eggert <7eggert@gmx.de>,
Christoph Raisch <raisch@de.ibm.com>,
Marcus Eder <meder@de.ibm.com>,
Stefan Roscher <stefan.roscher@de.ibm.com>
Subject: Re: RFC: issues concerning the next NAPI interface
Date: Fri, 24 Aug 2007 16:35:14 -0500 [thread overview]
Message-ID: <20070824213514.GL4282@austin.ibm.com> (raw)
In-Reply-To: <46CF499C.60009@de.ibm.com>
On Fri, Aug 24, 2007 at 11:11:56PM +0200, Jan-Bernd Themann wrote:
> (when they are available for
> POWER in our case).
hrtimer worked fine on the powerpc cell arch last summer.
I assume they work on p5 and p6 too, no ??
> I tried to implement something with "normal" timers, but the result
> was everything but great. The timers seem to be far too slow.
> I'm not sure if it helps to increase it from 1000HZ to 2500HZ
> or more.
Heh. Do the math. Even on 1gigabit cards, that's not enough:
(1gigabit/sec) x (byte/8 bits) x (packet/1500bytes) x (sec/1000 jiffy)
is 83 packets a jiffy (for big packets, even more for small packets,
and more again for 10 gigabit cards). So polling once per jiffy is a
latency disaster.
--linas
next prev parent reply other threads:[~2007-08-24 21:35 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8VHRR-45R-17@gated-at.bofh.it>
[not found] ` <8VKwj-8ke-27@gated-at.bofh.it>
2007-08-24 19:04 ` RFC: issues concerning the next NAPI interface Bodo Eggert
2007-08-24 20:42 ` Linas Vepstas
2007-08-24 21:11 ` Jan-Bernd Themann
2007-08-24 21:35 ` Linas Vepstas [this message]
2007-08-24 13:59 Jan-Bernd Themann
2007-08-24 15:37 ` akepner
2007-08-24 15:47 ` Jan-Bernd Themann
2007-08-24 15:52 ` Stephen Hemminger
2007-08-24 16:50 ` David Stevens
2007-08-24 21:44 ` David Miller
2007-08-24 21:51 ` Linas Vepstas
2007-08-24 16:51 ` Linas Vepstas
2007-08-24 17:07 ` Rick Jones
2007-08-24 17:45 ` Shirley Ma
2007-08-24 17:16 ` James Chapman
2007-08-24 18:11 ` Jan-Bernd Themann
2007-08-24 21:47 ` David Miller
2007-08-24 22:06 ` akepner
2007-08-26 19:36 ` James Chapman
2007-08-27 1:58 ` David Miller
2007-08-27 9:47 ` Jan-Bernd Themann
2007-08-27 20:37 ` David Miller
2007-08-28 11:19 ` Jan-Bernd Themann
2007-08-28 20:21 ` David Miller
2007-08-29 7:10 ` Jan-Bernd Themann
2007-08-29 8:15 ` James Chapman
2007-08-29 8:43 ` Jan-Bernd Themann
2007-08-29 8:29 ` David Miller
2007-08-29 8:31 ` Jan-Bernd Themann
2007-08-27 15:51 ` James Chapman
2007-08-27 16:02 ` Jan-Bernd Themann
2007-08-27 17:05 ` James Chapman
2007-08-27 21:02 ` David Miller
2007-08-27 21:41 ` James Chapman
2007-08-27 21:56 ` David Miller
2007-08-28 9:22 ` James Chapman
2007-08-28 11:48 ` Jan-Bernd Themann
2007-08-28 12:16 ` Evgeniy Polyakov
2007-08-28 14:55 ` James Chapman
2007-08-28 11:21 ` Jan-Bernd Themann
2007-08-28 20:25 ` David Miller
2007-08-28 20:27 ` David Miller
2007-08-24 16:45 ` Linas Vepstas
2007-08-24 21:43 ` David Miller
2007-08-24 21:32 ` David Miller
2007-08-24 21:37 ` David Miller
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