On Mon, Sep 13, 2010 at 03:38:41PM -0500, Tom Judge wrote: > On 09/13/2010 02:33 PM, Pyun YongHyeon wrote: > > On Mon, Sep 13, 2010 at 02:07:58PM -0500, Tom Judge wrote: > > > >> On 09/13/2010 01:48 PM, Pyun YongHyeon wrote: > >> > >>> On Mon, Sep 13, 2010 at 10:04:25AM -0500, Tom Judge wrote: > >>> > >>> > >>>> > >> <SNIP/> > >> > >>>> Does this mean that these cards are going to perform badly? This is was > >>>> what I gathered from the previous thread. > >>>> > >>>> > >>>> > >>> I mean there are still many rooms to be done in driver for better > >>> performance. bce(4) controllers are one of best controllers for > >>> servers and driver didn't take full advantage of it. > >>> > >>> > >>> > >> So far our experiences with bce(4) on FreeBSD have been very > >> disappointing. Starting with when Dell switched to bce(4) based NIC's > >> (around the time 6.2 was released and with the introduction of the Power > >> Edge X9XX hardware) we have always had problems with the driver in every > >> release we have used: 6.2, 7.0 and 7.1. Luckily David has been helpful > >> and helped us fix the issues. > >> > >> <SNIP/> > >> > >>> > >>> > >>>> Without BCE_JUMBO_HDRSPLIT then we see no errors. With it we see number > >>>> of errors, however the rate seems to be reduced compaired to the > >>>> previous version of the driver. > >>>> > >>>> > >>>> > >>> It seems there are issues in header splitting and it was disabled > >>> by default. Header splitting reduces packet processing overhead in > >>> upper layer so it's normal to see better performance with header > >>> splitting. > >>> > >>> > >> The reason that we have had header splitting enabled in the past is that > >> historically there have been issues with memory fragmentation when using > >> 8k jumbo frames (resulting in 9k mbuf's). > >> > >> > > Yes, if you use jumbo frames, header splitting would help to reduce > > memory fragmentation as header splitting wouldn't allocate jumbo > > clusters. > > > > > > Under testing I have yet to see a memory fragmentation issue with this > driver. I follow up if/when I find a problem with this again. > > >> I have a kernel with the following configuration in testing right now: > >> > >> * Flow control enabled. > >> * Jumbo header splitting turned off. > >> > >> > >> Is there any way that we can fix flow control with jumbo header > >> splitting turned on? > >> > >> > > Flow control has nothing to do with header splitting(i.e. flow > > control is always enabled). > > > > > Sorry let me rephrase that: > > Is there a way to fix the RX buffer shortage issues (when header > splitting is turned on) so that they are guarded by flow control. Maybe > change the low watermark for flow control when its enabled? >
I'm not sure how much it would help but try changing RX low watermark. Default value is 32 which seems to be reasonable value. But it's only for 5709/5716 controllers and Linux seems to use different default value. _______________________________________________ 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"
