Date: Fri, 8 Feb 2008 00:22:38 -0200 From: "Carlos A. M. dos Santos" <unixmania@gmail.com> To: freebsd-stable@freebsd.org Subject: Re: RELENG_7: interrupt eating whole cpu core Message-ID: <e71790db0802071822l661bdcb8s6dfe5b94be11f0dc@mail.gmail.com> In-Reply-To: <47AA0E3E.4020304@bsdforen.de> References: <47A9F835.1060200@bsdforen.de> <47AA0696.5020109@bsdforen.de> <7872AB6E-21DA-4E2D-93C0-D07CFA3A7E47@mac.com> <47AA0E3E.4020304@bsdforen.de>
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On Feb 6, 2008 5:45 PM, Dominic Fandrey <kamikaze@bsdforen.de> wrote:
> Chuck Swiger wrote:
> > Hi, Dominic--
> >
> > On Feb 6, 2008, at 11:12 AM, Dominic Fandrey wrote:
> >>> behaviour has changed. This is an HP 6510b GR695EA#ABD, if anyone
> >>> thinks it might be helpful, I can supply you with a dmesg and the
> >>> output of pciconf -lv.
> >>
> >> The problem remains with fresh sources:
> >>
> >> PID USERNAME THR PRI NICE SIZE RES STATE C TIME CPU COMMAND
> >> 12 root 1 171 ki31 0K 16K RUN 0 22:04 97.85%
> >> idle: cpu0
> >> 37 root 1 -64 - 0K 16K CPU1 1 2:35 96.00%
> >> irq14: ata0
> >> 11 root 1 171 ki31 0K 16K RUN 1 19:32 6.40%
> >> idle: cpu1
> >>
> >> The rip is done by k3b, so the drive is accessed through the cam
> >> interface.
> >
> > What are the values being reported by "sysctl hw.ata"? If you're going
> > to be burning CD/DVDs, you really want to make sure hw.ata.atapi_dma is on.
>
> I cannot believe it was so trivial. The sysctl looks all right.
>
> # sysctl hw.ata 0 /root
> hw.ata.wc: 1
> hw.ata.atapi_dma: 1
> hw.ata.ata_dma: 1
>
> But further research revealed:
> # atacontrol mode acd0 0 /root
> current mode = PIO4
>
> # atacontrol mode acd0 udma33 0 /root
>
> changed the load dramatically:
> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
> 12 root 1 171 ki31 0K 16K RUN 0 52:54 100.00% idle: cpu0
> 11 root 1 171 ki31 0K 16K CPU1 1 23:36 94.29% idle: cpu1
> 1087 kamikaze 3 -8 0 133M 36168K physrd 1 1:09 3.17% k3b
> 37 root 1 -64 - 0K 16K WAIT 1 30:10 0.00% irq14: ata0
>
>
> Thank you very much! I used to think that UDMA33 was the default for
> CD-/DVD-Rom drives. I suppose I should review the BIOS settings or change
> something in the hints file.
Wow, now I'm *really* surprised. I used to think that putting
hw.ata.ata_dma="1"
hw.ata.atapi_dma="1"
in /boot/loader.conf would be enough to enable DMA mode. In fact I'm
pretty sure it used to be in previous versions of FreeBSD. I created a
/etc/rc.local containing
#!/bin/sh -
atacontrol mode acd0 udma33
Two questions, now:
1. Is this related to using atapicam?
2. Should this be considered a bug?
--
Carlos A. M. dos Santos
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