Date: Wed, 20 Nov 2002 12:41:53 -0500 From: Don Bowman <don@sandvine.com> To: 'Terry Lambert' <tlambert2@mindspring.com>, hiten@unixdaemons.com Cc: tony@ubik.demon.co.uk, freebsd-hackers@freebsd.org Subject: RE: if_ti DEVICE_POLLING patch (Was: Re: [hackers] Re: Netgraphc ouldbe a router also) Message-ID: <FE045D4D9F7AED4CBFF1B3B813C8533701022FB8@mail.sandvine.com>
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> From: Terry Lambert [mailto:tlambert2@mindspring.com] > Hiten Pandya wrote: > > Hehe. I was not being sarcastic. I just acknoledged your > statement. The > > reason I asked about committing the patch in the first > place, is because I > > thought that the patch had been around on the -net@ list, > and had been reviewed. > > > > My apologies. > > It's been around on the list for a while, but if it's working for > the people involved, they are not saying anything. > > Last I heard, the person who had the problem had tried the Intel > Gigabit card, but not the Tigon III, but was looking for a Gigabit > card recommendation. > > I suppose I could make the same patch for the Intel card. > > The problem is that DEVICE_POLLING is an all-or-nothing thing, > you can't control it on a card-by-card basis, even with a > sysctl, because it fills out an entry point that's statically, > rather than procedurally initialized. Is there any point to using device polling with the tigon 3 (broadcom 570x etc)? It has a pretty good interrupt reducer in it by itself. Just tune the 2 rx and the 2 tx parameters and you get a constant interrupt rate with good latency for any packet rate. I changed (if_bge.c): /* RX Interrupt no more than every ~500 us */ sc->bge_rx_coal_ticks = 512; /* TX Interrupt no more than every ~500 us */ sc->bge_tx_coal_ticks = 512; /* RX Interrupt no more than every ~120 packets */ sc->bge_rx_max_coal_bds = 128; /* TX Interrupt no more than every ~120 packets */ sc->bge_tx_max_coal_bds = 128; and this gives no more than 2000 interrupts/s, and no more than 500us of latency. The if_em has similar functionality AFAIK. --don To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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