Date: Thu, 18 Jun 2009 18:19:25 +0400 From: Igor Sysoev <is@rambler-co.ru> To: Bruce Evans <brde@optusnet.com.au> Cc: freebsd-net@FreeBSD.org Subject: Re: bge interrupt coalescing sysctls Message-ID: <20090618141925.GG60354@rambler-co.ru> In-Reply-To: <20090611114120.I21056@delplex.bde.org> References: <20090610123301.GE40250@rambler-co.ru> <20090611114120.I21056@delplex.bde.org>
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On Thu, Jun 11, 2009 at 11:54:29AM +1000, Bruce Evans wrote: > On Wed, 10 Jun 2009, Igor Sysoev wrote: > > >For a long time I used Bruce Evans' patch to tune bge interrupt coalescing: > >http://lists.freebsd.org/pipermail/freebsd-net/2007-November/015956.html > >However, recent commit SVN r192478 in 7-STABLE (r192127 in HEAD) had broken > >the patch. I'm not sure how to fix the collision, and since I do not > >use dynamic tuning > > That commit looked ugly (lots of internal API changes and bloat in interrupt > handlers in many network drivers to support polling which mostly shouldn't > be supported at all and mostly doesn't use the interrupt handlers). > > >I has left only static coalescing parameters in the patch > >and has added a loader tunable to set number of receive descriptors and > >read only sysctl to read the tunable. I usually use these parameters: > > > >/boot/loader.conf: > >hw.bge.rxd=512 > > > >/etc/sysctl.conf: > >dev.bge.0.rx_coal_ticks=500 > >dev.bge.0.tx_coal_ticks=10000 > >dev.bge.0.rx_max_coal_bds=64 > > These rx settings give to high a latency for me. Probably, however, I use this on a host that has 6000 packets/s. > >dev.bge.0.tx_max_coal_bds=128 > ># apply the above parameters > >dev.bge.0.program_coal=1 > > > >Could anyone commit it ? > > Not me, sorry. > > The patch is quite clean. If I committed then I would commit the > dynamic coalescing configuration separately anyway. So have you any objections if some one else will commit this patch ? > You can probably make hw.bge.rxd a sysctl too (it would take a down/up > to get it changed, but that is already needed for too many parameters > in network drivers anyway). I should use a sysctl for the ifq length > too. This could be done at a high level for each driver. Limiting > queue lengths may be a good way to reduce cache misses, while increasing > them is sometimes good for reducing packet loss. Do you mean simple command sequence: sysctl hw.bge.rxd=512 ifconfig down ifconfig up or SYSCTL_ADD_PROC for hw.bge.rxd ? -- Igor Sysoev http://sysoev.ru/en/
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