From: Jason Lunz <lunz@gehennom.net>
To: James Chapman <jchapman@katalix.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, jeff@garzik.org,
mandeep.baines@gmail.com, ossthema@de.ibm.com, hadi@cyberus.ca,
Stephen Hemminger <shemminger@linux-foundation.org>
Subject: Re: RFC: possible NAPI improvements to reduce interrupt rates for low traffic rates
Date: Fri, 7 Sep 2007 16:20:47 -0500 [thread overview]
Message-ID: <20070907212044.GA9786@falooley.org> (raw)
In-Reply-To: <46E11A61.9030409@katalix.com>
In gmane.linux.network, you wrote:
> But the CPU has done more work. The flood ping will always show
> increased CPU with these changes because the driver always stays in the
> NAPI poll list. For typical LAN traffic, the average CPU usage doesn't
> increase as much, though more measurements would be useful.
I'd be particularly interested to see what happens to your latency when
other apps are hogging the cpu. I assume from your description that your
cpu is mostly free to schedule the niced softirqd for the device polling
duration, but this won't always be the case. If other tasks are running
at high priority, it could be nearly a full jiffy before softirqd gets
to check the poll list again and the latency introduced could be much
higher than you've yet measured.
Jason
next prev parent reply other threads:[~2007-09-07 22:03 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-06 14:16 RFC: possible NAPI improvements to reduce interrupt rates for low traffic rates James Chapman
2007-09-06 14:37 ` Stephen Hemminger
2007-09-06 15:30 ` James Chapman
2007-09-06 15:37 ` Stephen Hemminger
2007-09-06 16:07 ` James Chapman
2007-09-06 23:06 ` jamal
2007-09-07 9:31 ` James Chapman
2007-09-07 13:22 ` jamal
2007-09-10 9:20 ` James Chapman
2007-09-10 12:27 ` jamal
2007-09-12 7:04 ` Bill Fink
2007-09-12 12:12 ` jamal
2007-09-12 13:50 ` James Chapman
2007-09-12 14:02 ` Stephen Hemminger
2007-09-12 16:26 ` James Chapman
2007-09-12 16:47 ` Mandeep Baines
2007-09-13 6:57 ` David Miller
2007-09-14 13:14 ` jamal
2007-09-07 21:20 ` Jason Lunz [this message]
2007-09-10 9:25 ` James Chapman
2007-09-07 3:55 ` Mandeep Singh Baines
2007-09-07 9:38 ` James Chapman
2007-09-08 16:42 ` Mandeep Singh Baines
2007-09-10 9:33 ` James Chapman
2007-09-10 12:12 ` jamal
2007-09-08 16:32 ` Andi Kleen
2007-09-10 9:25 ` James Chapman
2007-09-12 15:12 ` David Miller
2007-09-12 16:39 ` James Chapman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20070907212044.GA9786@falooley.org \
--to=lunz@gehennom.net \
--cc=davem@davemloft.net \
--cc=hadi@cyberus.ca \
--cc=jchapman@katalix.com \
--cc=jeff@garzik.org \
--cc=mandeep.baines@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=ossthema@de.ibm.com \
--cc=shemminger@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).