From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH v3 1/6] net: pad skb data and shinfo as a whole rather than individually Date: Wed, 1 Feb 2012 09:39:47 +0000 Message-ID: <1328089187.17444.10.camel@zakaz.uk.xensource.com> References: <1327494389.24561.316.camel@zakaz.uk.xensource.com> <1327494434-21566-1-git-send-email-ian.campbell@citrix.com> <1327495879.2425.29.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1327496953.24561.323.camel@zakaz.uk.xensource.com> <1327497157.2425.34.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <1328020528.26983.396.camel@zakaz.uk.xensource.com> <1328021140.2297.10.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "netdev@vger.kernel.org" , "David S. Miller" To: Eric Dumazet Return-path: Received: from smtp.eu.citrix.com ([62.200.22.115]:25136 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753191Ab2BAJjt (ORCPT ); Wed, 1 Feb 2012 04:39:49 -0500 In-Reply-To: <1328021140.2297.10.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2012-01-31 at 14:45 +0000, Eric Dumazet wrote: > Le mardi 31 janvier 2012 =C3=A0 14:35 +0000, Ian Campbell a =C3=A9cri= t : > > Hi Eric, > >=20 > > On Wed, 2012-01-25 at 13:12 +0000, Eric Dumazet wrote: > > > Le mercredi 25 janvier 2012 =C3=A0 13:09 +0000, Ian Campbell a =C3= =A9crit : > > >=20 > > > > Can you elaborate on the specific benchmark you used there? > > >=20 > > > One machine was sending udp frames on my target (using pktgen) > > >=20 > > > Target was running a mono threaded udp receiver (one socket) > >=20 > > I've been playing with pktgen and I'm seeing more like 81,600-81,80= 0 pps > > from a UDP transmitter, measuring on the rx side using "bwm-ng -u > > packets" and sinking the traffic with "nc -l -u -p 9 > /dev/null". = The > > numbers are the same with or without this series. > >=20 > > You mentioned numbers in the 820pps region -- is that really kilo-p= ps > > (in which case I'm an order of magnitude down) or actually 820pps (= in > > which case I'm somehow a couple of orders of magnitude up). > >=20 > > I'm using a single NIC transmitter, no delay, 1000000 clones of eac= h skb > > and I've tried 60 and 1500 byte packets. In the 60 byte case I see = more > > like 50k pps > >=20 > > I'm in the process of setting up a receiver with a bnx2 but in the > > meantime I feel like I'm making some obvious or fundamental flaw in= my > > method... > >=20 > > Any tips greatly appreciated. >=20 > I confirm I reach 820.000 packets per second, on a Gigabit link. Heh, this is where $LOCALE steps up and confuses things again (commas v= s periods for thousands separators) ;-). However I know what you mean. > Sender can easily reach line rate (more than 1.000.000 packets per > second) Right, this is where I seem to have failed -- 10,000,000 took more like 2 minutes to send than the expected 10s... > Check how many packet drops you have on receiver ? >=20 > ifconfig eth0 >=20 > or "ethtool -S eth0" After a full 10,000,000 packet run of pktgen I see a difference in rx_packets of +10,001,561 (there is some other traffic). Various rx_*_error do not increase and neither does rx_no_buffer_count or rx_missed_errors (although both of the latter two are non-zero to start with). ifconfig tells the same story. I guess this isn't surprising given the send rate since it's not really stressing the receiver all that much. I'll investigate the sending side. The sender is running a 2.6.32 distr= o kernel. Maybe I need to tweak it somewhat. Thanks, Ian.