From: Andi Kleen <andi@firstfloor.org>
To: James Chapman <jchapman@katalix.com>
Cc: netdev@vger.kernel.org, hadi@cyberus.ca, davem@davemloft.net,
jeff@garzik.org, mandeep.baines@gmail.com, ossthema@de.ibm.com
Subject: Re: RFC: possible NAPI improvements to reduce interrupt rates for low traffic rates
Date: 08 Sep 2007 18:32:59 +0200 [thread overview]
Message-ID: <p737in19kxw.fsf@bingen.suse.de> (raw)
In-Reply-To: <200709061416.l86EG0Vb017675@quickie.katalix.com>
James Chapman <jchapman@katalix.com> writes:
>
> Clearly, keeping a device in polled mode for 1-2 jiffies
1-2 jiffies can be a long time on a HZ=100 kernel (20ms). A fast CPU
could do a lot of loops in this time, which would be waste of power
and CPU time.
On some platforms the precise timers (like ktime_get()) can be slow,
but often they are fast. It might make sense to use a shorter
constant time wait on those with fast timers at least. Right now this
cannot be known by portable code, but there was a proposal some time
ago to export some global estimate to tell how fast
ktime_get().et.al. are. That could be reviewed.
-Andi
next prev parent reply other threads:[~2007-09-08 16:33 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
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 [this message]
2007-09-10 9:25 ` James Chapman
2007-09-12 15:12 ` David Miller
2007-09-12 16:39 ` James Chapman
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