Date: Sat, 9 Sep 2006 07:00:15 +0000 From: Prafulla Deuskar <pdeuskar@freebsd.org> To: Pyun YongHyeon <pyunyh@gmail.com> Cc: freebsd-net <freebsd-net@freebsd.org>, freebsd-current <freebsd-current@freebsd.org>, Jack Vogel <jfvogel@gmail.com> Subject: Re: RFC: TSO patch for current Message-ID: <20060909070015.GA71855@hub.freebsd.org> In-Reply-To: <20060904075823.GA1210@cdnetworks.co.kr> References: <2a41acea0609011551v40338539u4eef48d091dd12ab@mail.gmail.com> <20060904075823.GA1210@cdnetworks.co.kr>
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Pyun YongHyeon [pyunyh@gmail.com] wrote: > On Fri, Sep 01, 2006 at 03:51:21PM -0700, Jack Vogel wrote: > > This is a patch for the stack and the em driver to enable TSO > > on CURRENT. Previously I had problems getting it to work, but > > this is functional. > > > > I should note that CURRENT is being a pain right now, when > > I comment out em in the config the kernel panics coming up, > > so I had to substitute this code into the tree. Rather bizarre :) > > > > I have this functionality running on a 6.1 based system, and > > our test group is already testing against that driver, so far > > things are looking good. > > > > I have designed it so the driver can continue to be built > > without support. There is also a sysctl in the stack code > > so you can set net.inet.tcp.tso_enable on or off and > > compare. > > > > I know there may be some refinements to add in, but I > > would like to get this into CURRENT as a start. > > > > Comments? > > > > It seems that 8254x also supports UDP segmentation offloading > feature. Have you tried to implement it? UDP requires IP fragmentation support in hardware - we don't support UDP offload. > According to the data sheet checksums are not accurate above 12K > frame size but I couldn't find frame size restrictions in TSO path. > What is maximum frame size supported by TSO? This is bounded by the MTU. > It seems that TSO assumes IP/TCP/UDP checksum offloading is always > enabled by hardware. What if users disable IP/TCP/UDP checksum > offloading with ifconfig(8)? TSO requires checksum offload - even if user disables checksum offload with ifconfig we will use it for TSO >What happen if users disable hardware > VLAN tag insertion with ifconfig(8)? TSO requires that VLAN tag insertion is done by hardware > It woud be even better if users can disable/enable TSO capability > for each network devices with ifconfig(8) instead of relying on > global sysctl MIB(net.inet.tcp.tso_enable). > > Btw, do you have benchmark numbers? > > > Jack > > -- > Regards, > Pyun YongHyeon > _______________________________________________ > 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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