On Wed, 21 Oct 2009 11:49:59 -0700 Kok, Auke wrote:
> Arjan van de Ven wrote:
> > On Wed, 21 Oct 2009 10:28:22 -0700
> > Randy Dunlap <randy.dun...@oracle.com> wrote:
> >
> >> From: Randy Dunlap <randy.dun...@oracle.com>
> >>
> >> Use a round_jiffies() variant to reduce overhead of timer
> >> wakeups. This causes the ipmi timers to occur at the same
> >> time as other timers (per CPU).
> >>
> >> Typical powertop for /ipmi/ (2.6.31, before patch):
> >> 11.4% (247.4) kipmi0 : __mod_timer (process_timeout)
> >> 0.6% ( 13.1) <interrupt> : ipmi_si
> >> 0.5% ( 10.0) <kernel core> : __mod_timer (ipmi_timeout)
> >>
> >> powertop for /ipmi/, 2.6.31, after patch:
> >> 10.8% (247.6) kipmi0 : __mod_timer (process_timeout)
> >> 0.3% ( 6.9) <interrupt> : ipmi_si
> >> 0.0% ( 1.0) <kernel core> : __mod_timer (ipmi_timeout)
> >
> > while it is nice that ipmi_si ande the timer wake up less now.... it's
> > still rather sad that the 247.6 from kipmi0 are still there..... those
> > are a much much bigger issue
>
> obviously :)
>
> Randy, any idea where those are coming from ?
obviously from kipmi thread :(
drivers/char/ipmi/ipmi_si_intf.c::ipmi_thread():
static int ipmi_thread(void *data)
{
struct smi_info *smi_info = data;
unsigned long flags;
enum si_sm_result smi_result;
set_user_nice(current, 19);
while (!kthread_should_stop()) {
spin_lock_irqsave(&(smi_info->si_lock), flags);
smi_result = smi_event_handler(smi_info, 0);
spin_unlock_irqrestore(&(smi_info->si_lock), flags);
if (smi_result == SI_SM_CALL_WITHOUT_DELAY)
; /* do nothing */
else if (smi_result == SI_SM_CALL_WITH_DELAY)
schedule();
else
schedule_timeout_interruptible(1); <-----
}
return 0;
}
calls setup_timer_on_stack(), which calls process_timeout().
>From what I recall (probably 2 years ago), [older] ipmi hardware does not
generate event interrupts, so it has to be polled.
Corey, can you elaborate on this?
---
~Randy
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