Date: Tue, 14 Sep 2004 22:32:06 -0700 From: Sandy Rutherford <sandy@krvarr.bc.ca> To: freebsd-questions@freebsd.org Cc: Gary Aitken <garya@dreamchaser.org> Subject: Re: shared irqs and performance Message-ID: <16711.54230.199600.66674@szamoca.krvarr.bc.ca> In-Reply-To: <b2807d0404091421516ce5efbc@mail.gmail.com> References: <41479332.3070108@dreamchaser.org> <b2807d0404091421516ce5efbc@mail.gmail.com>
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>>>>> On Wed, 15 Sep 2004 10:21:52 +0530, >>>>> Subhro <subhro.kar@gmail.com> said: > The card won't be facing any stability problems. And there is no > reason why you should force the card to another IRQ because modern > motherboards DOES allow IRQ sharing and there is no performance hits > for it. That's supposed to be the case and is usually the case. However, when left to its own devices, my Supermicro P6DBE board would always share an IRQ between a triple channel Mylex extremeRAID 1100 controller and one of the channels of a dual channel ZX348 ethernet card. When this happened, I would always see about 20% dropped packets on the ethernet channel sharing the IRQ. Manually overriding the IRQ assignment so that the RAID controller didn't share an IRQ with anything solved the problem. None-the-less, if there is no obvious evidence of odd behaviour, IRQ sharing is perfectly fine. However, if things are clearly not performing as they should, investigating potential IRQ sharing problems is not a bad idea. ...Sandy > Regards > S. > On Tue, 14 Sep 2004 18:56:18 -0600, Gary Aitken <garya@dreamchaser.org> wrote: >> On my 4.10 system, I added in a third ethernet device. >> >> However, I see from dmesg that the irq assigned is shared with my >> scsi controller: >> >> de1: <Digital 21041 Ethernet> port 0xf880-0xf8ff mem >> 0xfdfffc00-0xfdfffc7f irq 9 at device 16.0 on pci0 >> bt0: <Buslogic Multi-Master SCSI Host Adapter> port 0xfcec-0xfcef >> irq 9 at device 17.0 on pci0 >> >> Since the driver was already present, things went ok, in the sense >> that the system booted and scsi devices still work. >> >> 1. Will this work reliably (I haven't actually hooked anything >> to the new network card yet)? >> 2. Even if it does work, I assume it would be better to force >> it to an unused irq for performance reasons? >> >> Thanks, >> >> Gary >> _______________________________________________ >> freebsd-questions@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-questions >> To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" >> > -- > Subhro Sankha Kar > School of Information Technology > Block AQ-13/1 Sector V > ZIP 700091 > India > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"
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