Date: Fri, 18 Oct 2002 08:53:36 -0400 From: "Jim McGrath" <jimmcgra@bellatlantic.net> To: "Luigi Rizzo" <rizzo@icir.org> Cc: "Petri Helenius" <pete@he.iki.fi>, "Lars Eggert" <larse@ISI.EDU>, <freebsd-net@FreeBSD.ORG> Subject: RE: ENOBUFS Message-ID: <NDBBKKEELKBCJJBEGDECCEHJCGAA.jimmcgra@bellatlantic.net> In-Reply-To: <20021017215543.B76232@carp.icir.org>
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I have to tread carefully here because I was under NDA at my previous company. My work was with the wx driver, but hardware problems are hardware problems. There are a lot of performance enhancing features in the 82544. You will notice that the em driver does not use them. This may be for a reason :-( Our implementation ran with transmit interrupts disabled, so I can't comment on TIDV and am not allowed to comment on RIDV. The Receive Descriptor Threshold interrupt showed promise under high load (Rx interrupts disabled) but you would need to add a timeout function, 1 msec. or faster, to process receive descriptors under low load. Jim > -----Original Message----- > From: owner-freebsd-net@FreeBSD.ORG > [mailto:owner-freebsd-net@FreeBSD.ORG]On Behalf Of Luigi Rizzo > Sent: Friday, October 18, 2002 12:56 AM > To: Jim McGrath > Cc: Petri Helenius; Lars Eggert; freebsd-net@FreeBSD.ORG > Subject: Re: ENOBUFS > > > On Fri, Oct 18, 2002 at 12:49:04AM -0400, Jim McGrath wrote: > > Careful here. Read the errata sheet!! I do not believe the em > driver uses > > these parameters, and possibly for a good reason. > > as if i had access to the data sheets :) > > cheers > luigi > > Jim > > > > > -----Original Message----- > > > From: owner-freebsd-net@FreeBSD.ORG > > > [mailto:owner-freebsd-net@FreeBSD.ORG]On Behalf Of Luigi Rizzo > > > Sent: Thursday, October 17, 2002 11:12 PM > > > To: Petri Helenius > > > Cc: Lars Eggert; freebsd-net@FreeBSD.ORG > > > Subject: Re: ENOBUFS > > > > > > > > > On Thu, Oct 17, 2002 at 11:55:24PM +0300, Petri Helenius wrote: > > > ... > > > > I seem to get about 5-6 packets on an interrupt. Is this tunable? At > > > > > > just reading the source code, yes, it appears that the card has > > > support for delayed rx/tx interrupts -- see RIDV and TIDV definitions > > > and usage in sys/dev/em/* . I don't know in what units are the values > > > (28 and 128, respectively), but it does appear that tx interrupts are > > > delayed a bit more than rx interrupts. > > > > > > They are not user-configurable at the moment though, you need > to rebuild > > > the kernel. > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-net" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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