Date: Wed, 2 May 2012 17:28:45 -0400 From: Ryan Stone <rysto32@gmail.com> To: Navdeep Parhar <np@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: CPU selection for ithreads on 8.3 Message-ID: <CAFMmRNzHTqOasjq20e61o90PkZQ0vRWF9B-DWk=Qw3vO3CKdhg@mail.gmail.com> In-Reply-To: <4FA1A421.6020601@FreeBSD.org> References: <4FA1A421.6020601@FreeBSD.org>
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On Wed, May 2, 2012 at 5:16 PM, Navdeep Parhar <np@freebsd.org> wrote:
> There seems to be a regression in 8.3 in the way the kernel selects CPUs
> for interrupts. For example, cxgb(4) on 8.3 ends up with all
> its ithreads on the same CPU (CPU7 in this case).
>
> 12 root -68 - 0K 816K WAIT 7 0:55 0.00% intr{irq279:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:52 0.00% intr{irq275:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:47 0.00% intr{irq278:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:43 0.00% intr{irq277:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:43 0.00% intr{irq282:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:41 0.00% intr{irq281:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:32 0.00% intr{irq276:
> cxgbc0}
> 12 root -68 - 0K 816K WAIT 7 0:31 0.00% intr{irq280:
> cxgbc0}
>
> Back in the day there used to be code in cxgb to bind different
> interrupts to different CPUs but it was removed because the kernel
> distributed them across CPUs anyway. So what changed? This appears 8.3
> specific. I don't see it on head and I don't have a 9 system readily
> available right now.
Does r232757 fix this? That just missed 8.3-RELEASE.
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