Date: Fri, 25 Jan 2002 23:51:16 +0000 From: Neil McGann <neil@neilmcgann.co.uk> To: Kent Stewart <kstewart@owt.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: UDMA and 100Mbit NIC speed issues Message-ID: <5.1.0.14.0.20020125232753.00a2eec0@pop.ntlworld.com> In-Reply-To: <3C51D185.2090600@owt.com> References: <5.1.0.14.0.20020125204321.00a0f4c0@pop.ntlworld.com>
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>At 13:43 25/01/02 -0800, you wrote: Neil McGann wrote: > >I'm seeing a problem with network upload speed using 4.4-Release when the HD is in DMA mode. Basically the same as >problem report kern/32338, but the possible fix doesn't work for me. Machine is a ASUS Cuple-vm mobo (VIA PLE133), >400MHz celeron, Netgear FA311 NIC and IBM 60GX 60Gb deskstar on ULTRA100. Network is full-duplex thro a 100Mbit switch. >Symptom is ftp upload is very slow in DMA HD mode 5 and much faster in PIO mode. I see up/down of a (approx.) 100Mb file at >50s/29s in PIO and 3m50s/33s in UDMA. > >I have an ECS-K7S5A and an Amptron 830LM that have on board ATA-100 and 100Mps networking. I am consistently seeing >11MB/s transfers between the systems. There are usually some shared IRQ such as the AGP and the 1st PCI slot. When I >have an AGP video, I don't use the first slot. Common thread in both my machines is a VT82C686B southbridge. I've carefully selected the slots for no shared net/disk interrupts, but something is really stomping performance on receive. All these 100Mb net cards have comically small buffers, which I guess makes them really sensitive to chip-set parameters and latencies. It's interesting to watch the upload with UDMA disk - the first second-ish of transfers is quick, maybe at the 2Mb/sec rate and then it tapers away to around 450kb/sec. I've got a feeling that would be telling me something important if I knew how the TCP/IP stack worked ;-) Neil To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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