On Wed, May 30, 2007 at 12:55:51PM -0700, David Miller wrote:
> From: Patrick McHardy <[EMAIL PROTECTED]>
> Date: Wed, 30 May 2007 20:42:32 +0200
>
> > Stephen Hemminger wrote:
> > >>>Index: linux-2.6.22-rc-mm/net/sched/sch_generic.c
> > >>>===================================================================
> > >>>--- linux-2.6.22-rc-mm.orig/net/sched/sch_generic.c 2007-05-24
> > >>>11:16:03.000000000 -0700
> > >>>+++ linux-2.6.22-rc-mm/net/sched/sch_generic.c 2007-05-25
> > >>>15:10:02.000000000 -0700
> > >>>@@ -224,7 +224,8 @@
> > >>> if (dev->tx_timeout) {
> > >>> if (dev->watchdog_timeo <= 0)
> > >>> dev->watchdog_timeo = 5*HZ;
> > >>>- if (!mod_timer(&dev->watchdog_timer, jiffies +
> > >>>dev->watchdog_timeo))
> > >>>+ if (!mod_timer(&dev->watchdog_timer,
> > >>>+ round_jiffies(jiffies +
> > >>>dev->watchdog_timeo)))
> > >>> dev_hold(dev);
> > >>> }
> > >>> }
> > >>
> > >>Please cc netdev on net patches.
> > >>
> > >>Again, I worry that if people set the watchdog timeout to, say, 0.1
> > >>seconds
> > >>then they will get one second, which is grossly different.
> > >>
> > >>And if they were to set it to 1.5 seconds, they'd get 2.0 which is pretty
> > >>significant, too.
> > >
> > >
> > > Alternatively, we could change to a timer that is pushed forward after
> > > each
> > > TX, maybe using hrtimer and hrtimer_forward(). That way the timer would
> > > never run in normal case.
> >
> >
> > It seems wasteful to add per-packet overhead for tx timeouts, which
> > should be an exception. Do drivers really care about the exact
> > timeout value? Compared to a packet transmission time its incredibly
> > long anyways ..
>
> I agree, this change is absolutely rediculious and is just a blind
> cookie-cutter change made without consideration of what the code is
> doing and what it's requirements are.
I hope I could atleast highlight the issue here despite the cookie-cutter
patch..
On a totally idle system I have something like 85 wakeups for every 5 seconds
which I am trying to reduce (to reduce the power consumption and increase
battery life. And 1 interrupt out of 85 happens to be netdev watchdog timer.
Thanks,
Venki
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