RE: [PATCH] x86-64 highres/dyntick support

From: Pallipadi, Venkatesh
Date: Tue May 08 2007 - 09:15:48 EST




>-----Original Message-----
>From: Chris Wright [mailto:chrisw@xxxxxxxxxxxx]
>Sent: Tuesday, May 08, 2007 2:52 AM
>To: Thomas Gleixner
>Cc: Chris Wright; LKML; Pallipadi, Venkatesh; john stultz;
>Ingo Molnar; Arjan van de Ven; Steven Rostedt; Andi Kleen;
>Andrew Morton
>Subject: Re: [PATCH] x86-64 highres/dyntick support
>
>* Thomas Gleixner (tglx@xxxxxxxxxxxxx) wrote:
>> On Tue, 2007-05-08 at 02:39 -0700, Chris Wright wrote:
>>
>> > OK, looks very similar all things considered. One thing I
>didn't do
>> > was fix lapic timer calibration (was hoping you'd do that
>part, and you
>> > did ;-) I've noticed that something has changed and I'm
>seeing irq0
>> > handled on cpu3 (4 cpu system), where it used to be on
>cpu0 as expected.
>>
>> Strange, irq balancing ?
>
>That's what I was wondering, although i have same setup for 32-bit
>and it behaves as expected with cpu0 taking hpet or pit on irq0
>and lapic timer picked up on the other 3 cpus.
>

Yes. Looks like irq balancing issue. On i386 I see irq has flag
IRQF_NOBALANCING, but x86-64 does not have this flag. Can you add that
and check whether that makes any difference.

Thanks,
Venki
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