Stephen Hemminger wrote:

quoted

quoted

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 ..