Date: Mon, 17 Aug 1998 07:55:38 -0500 From: Carroll Kong <damascus@eden.rutgers.edu> To: Paul van der Zwan <paulz@trantor.stuyts.nl>, current@FreeBSD.ORG Subject: Re: Cards sharing irq's on PCI bus Message-ID: <199808171152.EAA26919@hub.freebsd.org> In-Reply-To: <199808171104.NAA23662@trantor.stuyts.nl>
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At 01:04 PM 8/17/98 +0200, Paul van der Zwan wrote: >I am running very low on available irq's and I noticed that the bios put both >my SMC 8432BT and my Adaptec 2740 on irq 9. Network performance was terrible, >iozone on NFS only 300kB/s. After disabling my IDE controller (only need that >when running Solaris) the Adaptrec was put on irq 14 (where the IDE used to be) >and my network performance was back ( more than 900kB/s). > >Is it allowed to put have more than one PCI card use the same irq ??? >It sort of worked. No errors or so, just lousy performance ?? >Maybe someone can shed some light on this ?? > > > Paul For MS Oses, PCI Irq sharing is pretty "safe"... at least in the foreground... who knows if it really works 100%. But.. I quad boot... so when I go to a Unix OS.. I want 100% workability.. or at least 99.9%... :) I tried pci irq sharing and found problems immediately when sharing a NIC with a SCSI card. (3Com would not work.. kernel had problems with linux... I didn't even bother with booting into FreeBSD to see what kind of errors I would get there.. hehe all for one... one for all) Usually, the safest one to irq share is your video card. Technically it doesn't need an irq... (I would do it though), share the video irq with another device like the NIC. Check performance again. Should be similar... if not the same. (I am going to test my NIC performance now that it is shared.... Hm... need large contiguous file.... I should use dd if=/dev/zero of=contig.file bs=1024000 count=5? Wil that make a 5 meg file named contig.file?) -Carroll Kong To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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