Date: Sun, 6 Nov 2011 10:49:57 -0500 (EST) From: Rick Macklem <rmacklem@uoguelph.ca> To: bevan@bi-co.net Cc: freebsd-net@freebsd.org, Adrian Chadd <adrian@freebsd.org> Subject: Re: Gigabit Ethernet performance with Realtek 8111E Message-ID: <1699972836.1240239.1320594597659.JavaMail.root@erie.cs.uoguelph.ca> In-Reply-To: <1320580923.19667.65.camel@bevan-pc.fritz.box>
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Michael wrote: > Hi! > > Am Samstag, den 05.11.2011, 11:03 -0400 schrieb Rick Macklem: > > try typing: > > # sysctl dev.re.0.stats=1 > > - this will dump out the stats on the chip > > if the "Rx missed frames" count is non-zero, you're probably > > snookered, > > to put it technically:-) > > - That's what I get for a re chip is this laptop and I haven't > > found > > a way around it. I just live with flakey net performance. > > Rx missed frames is >0 indeed. Every time I see those drops in speed > the > number of missed frames increases by approx. 20-50. > > When searching for this problem I found your old thread on > freebsd-current[1]. It seems that the problem is way less severe here. > Some transfers even don't cause any problems. Others however spend > more > time at 0kbit/s than actually transferring data... > It also seems like transfers are stabilizing after some seconds but > that > is not always the case. > In good times the rate of missed frames is below 0.01%. > > I think the Dup ACKs are just a result of these lost packages. I do > not > see them always when these problems occur. > > Was there any progress after your last mail on 8th of Nov.? > Nope. For my case, when Rx frames are missed, there is a Fifo overflow reported. I'm no hardware guy, but my understanding is that, sometimes, the dma engine transferring data to the receive buffers doesn't keep up and the fifo fills up. I did try assorted hacks on the driver, but none of them got rid of the problem. For my case the combination of these two things did reduce the # of Rx packets missed, but not down to 0. - disable msi interrupts (there's an option in the driver) - comment out the few lines of code that disabled/re-enabled interrupts (I don't think this code is broken, but for some reason, leaving the interrupts enabled reduced the # of Rx missed for this laptop. Maybe the dma engine stops running when interrupts are being switched on/off? Just pure conjecture, of course.) Also, only both of the above together made a difference. Each one individually didn't help. I heard that there was a driver for BSD out there somewhere that puts all the Realtek chips in 8139 compatible mode and drives them that way, but I never even gotten as far as searching for this driver. Good luck with it, rick > Greetings, > Michael > > [1]: > http://lists.freebsd.org/pipermail/freebsd-current/2010-October/020793.html > http://lists.freebsd.org/pipermail/freebsd-current/2010-November/020797.html > > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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