Re: [patch 00/21] high resolution timers / dynamic ticks - V2

[Ingo Molnar]

* Andrew Morton <akpm@xxxxxxxx> wrote:

> These patches make my Vaio run really really slowly.  Maybe a quarter 
> of the normal speed or lower.  Bisection shows that the bug is 
> introduced by 
> clockevents-drivers-for-i386.patch+clockevents-drivers-for-i386-fix.patch
> 
> With all patches applied, the slowdown happens with 
> CONFIG_HIGH_RES_TIMERS=n and also with CONFIG_HIGH_RES_TIMERS=y && 
> CONFIG_NO_HZ=y.  So something got collaterally damaged.

yeah, i suspect it works again if you disable:

 CONFIG_X86_UP_APIC=y
 CONFIG_X86_UP_IOAPIC=y
 CONFIG_X86_LOCAL_APIC=y
 CONFIG_X86_IO_APIC=y

as the slowdown has the feeling of a runaway lapic timer irq.

from code review so far we can only see an udelay(10) difference in the 
initialization sequence of the PIT - we'll send a fix for that but i 
dont think that's the cause of the bug.

investigating it.

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/