From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamal Subject: Re: [e1000 2.6 10/11] TxDescriptors -> 1024 default Date: 11 Sep 2003 21:34:23 -0400 Sender: netdev-bounce@oss.sgi.com Message-ID: <1063330463.1028.8.camel@jzny.localdomain> References: <3F60CA6D.9090503@pobox.com> <3F60D0F3.8080006@candelatech.com> <20030911131219.0ab8dfdd.davem@redhat.com> <3F60DDCC.5020906@candelatech.com> <20030911140746.4f0384a1.davem@redhat.com> <3F60E947.4090005@candelatech.com> <20030911142906.74d9dfe5.davem@redhat.com> <3F60F3F7.6090203@candelatech.com> <20030911160252.6cd6c07d.davem@redhat.com> <3F6103BB.5030706@candelatech.com> Reply-To: hadi@cyberus.ca Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: jgarzik@pobox.com, scott.feldman@intel.com, netdev@oss.sgi.com, ricardoz@us.ibm.com Return-path: To: Ben Greear In-Reply-To: <3F6103BB.5030706@candelatech.com> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Scott, dont increase the tx descriptor ring size - that would truly wasting memory; 256 is pretty adequate. * increase instead the txquelen (as suggested by Davem); user space tools like ip or ifconfig could do it. The standard size has been around 100 for 100Mbps; i suppose it is fair to say that Gige can move data out at 10x that; so set it to 1000. Maybe you can do this from the driver based on what negotiated speed is detected? -------- [root@jzny root]# ip link ls eth0 4: eth0: mtu 1500 qdisc pfifo_fast qlen 100 link/ether 00:b0:d0:05:ae:81 brd ff:ff:ff:ff:ff:ff [root@jzny root]# ip link set[root@jzny root]# ip link ls eth0 4: eth0: mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:b0:d0:05:ae:81 brd ff:ff:ff:ff:ff:ff eth0 txqueuelen 1000 ------- TCP already reacts on packets dropped at the scheduler level, UDP would be too hard to enforce since the logic is typically on an app above udp. So just conrtol it via the socket queue size. cheers, jamal On Thu, 2003-09-11 at 19:22, Ben Greear wrote: > David S. Miller wrote: > > On Thu, 11 Sep 2003 15:15:19 -0700 > > Ben Greear wrote: > > > > > >>And the original poster shows how a similar problem slows down TCP > >>as well due to local dropped packets. > > > > > > So, again, dampen the per-socket send queue sizes. > > That's just a band-aid to cover up the flaw with the lack > of queue-pressure feedback to the higher stacks, as would be increasing the > TxDescriptors for that matter.