On 28.04.2011 14:29, Adam Stylinski wrote: > Hello, > > I have an intel gigabit network adapter (the 1000 GT w/chipset 82541PI) which > performs poorly in Freebsd compared to the same card in Linux. I've tried > this card in two different freebsd boxes and for whatever reason I get poor > transmit performance. I've done all of the tweaking specified in just about > every guide out there (the usual TCP window scaling, larger nmbclusters, > delayed acks, etc) and still I get only around 600mbps. I'm using jumbo > frames, with an MTU of 9000. I'm testing this with iperf. While I realize > that this may not be the most realistic test, linux hosts with the same card > can achieve 995Mbit/s to another host running this. When the Freebsd box is > the server, Linux hosts can transmit to it at around 800 something Mbit/s. > I've increased the transmit descriptors as specified in the if_em man page, > and while that gave me 20 or 30 more mbit/s, my transmit performance is still > below normal. > > sysctl stats report that the card is trigger a lot of tx_desc_fail2: > dev.em.0.tx_desc_fail2: 3431 > > Looking at a comment in the source code this indicates that the card was not > able to obtain enough transmit descriptors (but I've given the card the > maximum of 4096 in my loader.conf tunable). Is this a bug or a performance > regression of some kind? Does anybody have a fix for this? I tried another > card with the same chip in a different box on 8-STABLE to no avail (the box > I'm trying to improve performance on is on 8.2-RELEASE-p1). > > Anybody manage to make this card push above 600mbps in ideal network > benchmarks? Any help would be gladly appreciated.
Please show output of "vmstat -z|egrep 'ITEM|mbuf'" command after the test. Eugene Grosbein _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
