Date: Wed, 24 Oct 2012 08:38:01 -0700 From: Jack Vogel <jfvogel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: Garrett Cooper <yanegomi@gmail.com>, freebsd-net@freebsd.org, Jack F Vogel <jfv@freebsd.org> Subject: Re: ixgb TSO performance degrades by ~30% between 7.4 and 8.2/9.0/9.1 Message-ID: <CAFOYbcmUSfEUcQa38HF_dk5CzPUBFa0gpAA%2BfLqjPjgL6V-sHQ@mail.gmail.com> In-Reply-To: <201210241107.10775.jhb@freebsd.org> References: <CAGH67wTjVw8O7i9OCvHVJjVjCAXsNHNhs0LobDi4G9iukgf%2BeQ@mail.gmail.com> <201210241107.10775.jhb@freebsd.org>
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On Wed, Oct 24, 2012 at 8:07 AM, John Baldwin <jhb@freebsd.org> wrote: > On Tuesday, October 23, 2012 6:57:01 pm Garrett Cooper wrote: > > Hi, > > > > Doing some poking around at the ixgb driver with a card I have at > > $work using netperf and two machines hooked up over crossover, I > > discovered that while ixgb's throughput performance was fantastic on > > 7.3/7.4, thoughput performance of the card is degraded on 8.2/9.0/9.1 > > by ~30% (9400Mbps on 7.4 -> 6294Mbps on 9.0 for example). LRO > > performance on the other hand is fantastic and doesn't degrade with > > the card across FreeBSD versions. Performance remains constant with > > ixgb across 8.2/9.0/9.1. I didn't observe the CPU usage. > > Interesting, maybe as an experiment try hacking the #ifdef's to use > if_start() instead of if_transmit(). > > That's not a bad idea, I have had cases, for instance some UDP intensive loads, where I found better performance with the old interface. This was one reason why I had wanted to change the ifdef's to not just be an OS version level, making either more easily selectable. Jack
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