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RE: xfslogd on SMP systems

To: linux-xfs@xxxxxxxxxxx
Subject: RE: xfslogd on SMP systems
From: Scott Jepson <scott@xxxxxxxx>
Date: Fri, 4 Apr 2003 09:35:13 -0800
In-reply-to: <F341E03C8ED6D311805E00902761278C0C35E4C6@xfc04.fc.hp.com>
Sender: linux-xfs-bounce@xxxxxxxxxxx
Erik,
 Which patches did you use for the interrupt balancing? Do you
have a URL to them? I would like to try them out also.

Thanks,
 -Scott


On Fri, 4 Apr 2003, HABBINGA,ERIK (HP-Loveland,ex1) wrote:

> Date: Fri, 4 Apr 2003 12:01:20 -0500
> From: "HABBINGA,ERIK (HP-Loveland,ex1)" <erik.habbinga@xxxxxx>
> To: 'Steve Lord' <lord@xxxxxxx>
> Cc: "'linux-xfs@xxxxxxxxxxx'" <linux-xfs@xxxxxxxxxxx>
> Subject: RE: xfslogd on SMP systems
>
> > It is being reworked. The threads handle I/O completion on a per cpu
> > basis, interrupts hand work off to the thread on the same cpu. Xeons
> > deliver all their interrupts to cpu 0 by default, so all the work
> > goes one place. Ask intel about this one.
> >
> > If you actually have multiple controllers involved then you can
> > get hold of irqbalance which will distribute the interrupts from
> > different controllers around the cpus.
> >
> > This xeon issue is why we decided to rework this.
> >
>
> I already have kernel patches that redistribute the irq's from our storage
> controllers across all cpus.  Here's some output from /proc/interrupts:
>
>   0:      56540      57588      57045      56213    IO-APIC-edge  timer
>  16:     810276     788003     778844     770226   IO-APIC-level  lpfcdd
>  18:     818436     797352     795307     787978   IO-APIC-level  lpfcdd
>
> I can't find any good description of irqbalance, but it looks to do the same
> thing in a user space daemon.  With those kernel patches, xfslogd/0 is still
> the only process consuming CPU time.  Is there something else I should check
> or try?
>
> Erik
>
> > Steve
> >
> > --
> >
> > Steve Lord                                      voice: +1-651-683-3511
> > Principal Engineer, Filesystem Software         email: lord@xxxxxxx
> >
>
>
>


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