From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Venkat Subbiah <vsubbiah@caviumnetworks.com>
Cc: RT <linux-rt-users@vger.kernel.org>
Subject: Re: task switch from net-rx to idle when there is napi processing to be done
Date: Wed, 25 Jan 2012 09:55:23 +0100 [thread overview]
Message-ID: <20120125085523.GG6305@pengutronix.de> (raw)
In-Reply-To: <4F1F6B66.5010005@caviumnetworks.com>
Hello,
On Tue, Jan 24, 2012 at 06:39:34PM -0800, Venkat Subbiah wrote:
> In the process of debugging a napi ethernet driver performance
> issue, what I am noticing is
>
> 1. While the driver is in the middle of a napi packet processing
> loop, there is a task switch from
> sirq-net-rx to idle even though there is pending napi processing to be done.
I didn't check your logs below, but maybe this is related to the default
settings in /proc/sys/kernel/sched_rt_period_us and
/proc/sys/kernel/sched_rt_runtime_us? That is 0.05s per second is
reserved for non-RT tasks tasks such that a run-away realtime process
will not lock up the machine.
To verify that, try
echo -1 > /proc/sys/kernel/sched_rt_runtime_us
.
Best regards
Uwe
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Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2012-01-25 8:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-25 2:39 task switch from net-rx to idle when there is napi processing to be done Venkat Subbiah
2012-01-25 8:55 ` Uwe Kleine-König [this message]
2012-01-25 9:18 ` Mike Galbraith
2012-01-25 11:40 ` Venkat Subbiah
2012-01-25 11:30 ` Venkat Subbiah
2012-01-26 15:29 ` Steven Rostedt
2012-01-26 20:35 ` Venkat Subbiah
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