From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next] softirq: reduce latencies Date: Thu, 03 Jan 2013 05:31:59 -0800 Message-ID: <1357219919.21409.24519.camel@edumazet-glaptop> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, LKML To: sedat.dilek@gmail.com Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, 2013-01-03 at 14:12 +0100, Sedat Dilek wrote: > Hi Eric, > > your patch from [2] applies cleanly on top of Linux v3.8-rc2. > I would like to test it. > In [1] you were talking about benchmarks you did. > Can you describe them or provide a testcase (script etc.)? > You made only network testing? Yes I did network testing : - net_rx_action() softirq handler is the typical function that can consume 2 ms per call. I did some netperf sessions, with multiqueue 10G nics, tuned to that IRQ would be handled by few cpus. (check /proc/irq/*/eth0-$QUEUE/../smp_affinity ) Another way to make the softirq processing use more cpu cycles is by adding a fake iptable setup like : for n in `seq 1 100` do iptables -I INPUT done A common network load is to launch ~200 concurrent TCP_RR netperf sessions like the following netperf -H remote_host -t TCP_RR -l 1000 And then you can launch some netperf asking P99_LATENCY results : netperf -H remote_host -t TCP_RR -- -k P99_LATENCY You can play with taskset or netperf option -T to force netperf/netserver running on given cpus.