Re: [RFC][PATCH] TIMER_BH-less smptimers

From: Anton Blanchard (anton@samba.org)
Date: Mon May 20 2002 - 03:55:00 EST


Hi Dipankar,

> I have been experimenting with Ingo's smptimers and I ended up
> extending it a little bit. I would really appreciate comments
> on whether these things make sense or not.

I tried it out and found that we were context switching like crazy.
It seems we were always running the timers out of a tasklet because
we never unlocked the net_bh_lock.

Anton

diff -urN linux-2.5_smptimers/kernel/timer.c linux-2.5_tux/kernel/timer.c
--- linux-2.5_smptimers/kernel/timer.c Mon May 20 18:48:18 2002
+++ linux-2.5_tux/kernel/timer.c Mon May 20 18:41:32 2002
@@ -694,6 +694,7 @@
                 __run_timers(base);
 
         hardirq_endlock(cpu);
+ spin_unlock(&net_bh_lock);
         spin_unlock(&global_bh_lock);
         return;
 resched_net:
@@ -733,6 +734,7 @@
                 __run_timers(base);
 
         hardirq_endlock(cpu);
+ spin_unlock(&net_bh_lock);
         spin_unlock(&global_bh_lock);
         local_irq_enable();
         local_bh_enable();
-
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