Date: Tue, 06 Apr 1999 09:03:34 +0100 From: Karl Pielorz <kpielorz@tdx.co.uk> To: Ken Brownfield <kenb@irridia.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Disk I/O crushes Ethernet I/O (3.0R) Message-ID: <3709BFD6.A1BC378@tdx.co.uk> References: <199904060731.CAA10029@asooo.irridia.com>
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Ken Brownfield wrote: > > [snip] > > SuperMicro P6DLE > Dual P2/233, 340MB RAM > 12GB IDE drive > Intel EtherExpress PRO/100B on 10BT network > > During periods of disk activity (copying a large file, etc.) all > network traffic virtually comes to a halt. If I run the cp during > an FTP file transfer, my network transfer rate is dropped by about > 80%. Other network services suffer the same massive packet > deprivation. Are you using DMA with the IDE drive? (and are you _sure_ your using DMA with the IDE drive? :) > This doesn't seem to be an MBUF problem, and I haven't been able > to find a specific mention of this sort of problem. Is this > something inherent with the kernel, the IDE driver, the fxp driver, > or FreeBSD's SMP implementation? Or is this most likely an IRQ > conflict or bad IRQ choice for the ether card? I have a similar setup here (Dual P-Pro, 256Mb RAM, fxp0, IDE + SCSI). The IDE drives suck, even with DMA etc. - they're no match for 'decent' SCSI drives (but they are cheap). They're OK for 'straight line speed', but I find for multi-process access/heavy loads SCSI wins hands down (if only for the fact most decent SCSI drives have >512k cache + faster spindle speeds). I've noticed FreeBSD's SMP implementation is a bit choppy sometimes, but not to that extent... Of course there could just be simple maths involved, if you only have 1 hard drive, and your doing a CP (from itself to iteself?) and then ftp a file to/from that same drive, 3 into 1 isn't going to fit at any reasnably speed... :) -Kp To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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