From owner-freebsd-smp@FreeBSD.ORG Mon Nov 17 11:11:01 2008 Return-Path: Delivered-To: freebsd-smp@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 685861065678 for ; Mon, 17 Nov 2008 11:11:01 +0000 (UTC) (envelope-from archimedes.gaviola@gmail.com) Received: from rv-out-0506.google.com (rv-out-0506.google.com [209.85.198.236]) by mx1.freebsd.org (Postfix) with ESMTP id 3A05D8FC1B for ; Mon, 17 Nov 2008 11:11:00 +0000 (UTC) (envelope-from archimedes.gaviola@gmail.com) Received: by rv-out-0506.google.com with SMTP id b25so2282955rvf.43 for ; Mon, 17 Nov 2008 03:11:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=fGVHgR0LABWszzv9fduqH285vli6uWOgvFgOhzs4J3Q=; b=MuS42+YF1eisZG4dwOyGA15agH5ASE+eZIWNhCd89OFWkJZflXhaE1/Q/yeIOtEs/d nYwy9V6nHQ8Y5uUfXWAJrR6C009wMNQ6Yg/t9AtB/yDPoEyliej8hm4xbTtJrxHP3RE+ Latd+u7MhXF7DLqqv17FOGhIgEU5HFvsJ9AfM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=Udn6JI+XZq/VnqSTH8pv6xYfZ6UbRTJD4aHGcj7JY2g51CupdupAjPU/JGoMniTbwB wuKl01sT7CRNci6PxutKnQM2zQ6+jGoNl/DNAd0e5CzISFmg20DJX9r057baDgM0MWzt YqlKr6yoXAlj81PiRSXqzoIXk7i3ypLtydP0M= Received: by 10.114.174.2 with SMTP id w2mr2415221wae.195.1226920260630; Mon, 17 Nov 2008 03:11:00 -0800 (PST) Received: by 10.115.76.12 with HTTP; Mon, 17 Nov 2008 03:11:00 -0800 (PST) Message-ID: <42e3d810811170311uddc77daj176bc285722a0c8@mail.gmail.com> Date: Mon, 17 Nov 2008 19:11:00 +0800 From: "Archimedes Gaviola" To: "John Baldwin" In-Reply-To: <200811131128.55220.jhb@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <42e3d810811100033w172e90dbl209ecbab640cc24f@mail.gmail.com> <200811111216.37462.jhb@freebsd.org> <42e3d810811130355x3857bceap447e134b18eee04b@mail.gmail.com> <200811131128.55220.jhb@freebsd.org> Cc: freebsd-smp@freebsd.org Subject: Re: CPU affinity with ULE scheduler X-BeenThere: freebsd-smp@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: FreeBSD SMP implementation group List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Nov 2008 11:11:01 -0000 On Fri, Nov 14, 2008 at 12:28 AM, John Baldwin wrote: > On Thursday 13 November 2008 06:55:01 am Archimedes Gaviola wrote: >> On Wed, Nov 12, 2008 at 1:16 AM, John Baldwin wrote: >> > On Monday 10 November 2008 11:32:55 pm Archimedes Gaviola wrote: >> >> On Tue, Nov 11, 2008 at 6:33 AM, John Baldwin wrote: >> >> > On Monday 10 November 2008 03:33:23 am Archimedes Gaviola wrote: >> >> >> To Whom It May Concerned: >> >> >> >> >> >> Can someone explain or share about ULE scheduler (latest version 2 if >> >> >> I'm not mistaken) dealing with CPU affinity? Is there any existing >> >> >> benchmarks on this with FreeBSD? Because I am currently using 4BSD >> >> >> scheduler and as what I have observed especially on processing high >> >> >> network load traffic on multiple CPU cores, only one CPU were being >> >> >> stressed with network interrupt while the rests are mostly in idle >> >> >> state. This is an AMD-64 (4x) dual-core IBM system with GigE Broadcom >> >> >> network interface cards (bce0 and bce1). Below is the snapshot of the >> >> >> case. >> >> > >> >> > Interrupts are routed to a single CPU. Since bce0 and bce1 are both on >> > the >> >> > same interrupt (irq 23), the CPU that interrupt is routed to is going > to >> > end >> >> > up handling all the interrupts for bce0 and bce1. This not something > ULE >> > or >> >> > 4BSD have any control over. >> >> > >> >> > -- >> >> > John Baldwin >> >> > >> >> >> >> Hi John, >> >> >> >> I'm sorry for the wrong snapshot. Here's the right one with my concern. >> >> >> >> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND >> >> 17 root 1 171 52 0K 16K CPU0 0 54:28 95.17% idle: > cpu0 >> >> 15 root 1 171 52 0K 16K CPU2 2 55:55 93.65% idle: > cpu2 >> >> 14 root 1 171 52 0K 16K CPU3 3 58:53 93.55% idle: > cpu3 >> >> 13 root 1 171 52 0K 16K RUN 4 59:14 82.47% idle: > cpu4 >> >> 12 root 1 171 52 0K 16K RUN 5 55:42 82.23% idle: > cpu5 >> >> 16 root 1 171 52 0K 16K CPU1 1 58:13 77.78% idle: > cpu1 >> >> 11 root 1 171 52 0K 16K CPU6 6 54:08 76.17% idle: > cpu6 >> >> 36 root 1 -68 -187 0K 16K WAIT 7 8:50 65.53% >> >> irq23: bce0 bce1 >> >> 10 root 1 171 52 0K 16K CPU7 7 48:19 29.79% idle: > cpu7 >> >> 43 root 1 171 52 0K 16K pgzero 2 0:35 1.51% > pagezero >> >> 1372 root 10 20 0 16716K 5764K kserel 6 58:42 0.00% kmd >> >> 4488 root 1 96 0 30676K 4236K select 2 1:51 0.00% sshd >> >> 18 root 1 -32 -151 0K 16K WAIT 0 1:14 0.00% swi4: >> > clock s >> >> 20 root 1 -44 -163 0K 16K WAIT 0 0:30 0.00% swi1: > net >> >> 218 root 1 96 0 3852K 1376K select 0 0:23 0.00% syslogd >> >> 2171 root 1 96 0 30676K 4224K select 6 0:19 0.00% sshd >> >> >> >> Actually I was doing a network performance testing on this system with >> >> FreeBSD-6.2 RELEASE using its default scheduler 4BSD and then I used a >> >> tool to generate big amount of traffic around 600Mbps-700Mbps >> >> traversing the FreeBSD system in bi-direction, meaning both network >> >> interfaces are receiving traffic. What happened was, the CPU (cpu7) >> >> that handles the (irq 23) on both interfaces consumed big amount of >> >> CPU utilization around 65.53% in which it affects other running >> >> applications and services like sshd and httpd. It's no longer >> >> accessible when traffic is bombarded. With the current situation of my >> >> FreeBSD system with only one CPU being stressed, I was thinking of >> >> moving to FreeBSD-7.0 RELEASE with the ULE scheduler because I thought >> >> my concern has something to do with the distributions of load on >> >> multiple CPU cores handled by the scheduler especially at the network >> >> level, processing network load. So, if it is more of interrupt >> >> handling and not on the scheduler, is there a way we can optimize it? >> >> Because if it still routed only to one CPU then for me it's still >> >> inefficient. Who handles interrupt scheduling for bounding CPU in >> >> order to prevent shared IRQ? Is there any improvements with >> >> FreeBSD-7.0 with regards to interrupt handling? >> > >> > It depends. In all likelihood, the interrupts from bce0 and bce1 are both >> > hardwired to the same interrupt pin and so they will always share the same >> > ithread when using the legacy INTx interrupts. However, bce(4) parts do >> > support MSI, and if you try a newer OS snap (6.3 or later) these devices >> > should use MSI in which case each NIC would be assigned to a separate CPU. > I >> > would suggest trying 7.0 or a 7.1 release candidate and see if it does >> > better. >> > >> > -- >> > John Baldwin >> > >> >> Hi John, >> >> I try 7.0 release and each network interface were already allocated >> separately on different CPU. Here, MSI is already working. >> >> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND >> 12 root 1 171 ki31 0K 16K CPU6 6 123:55 100.00% idle: > cpu6 >> 15 root 1 171 ki31 0K 16K CPU3 3 123:54 100.00% idle: > cpu3 >> 14 root 1 171 ki31 0K 16K CPU4 4 123:26 100.00% idle: > cpu4 >> 16 root 1 171 ki31 0K 16K CPU2 2 123:15 100.00% idle: > cpu2 >> 17 root 1 171 ki31 0K 16K CPU1 1 123:15 100.00% idle: > cpu1 >> 37 root 1 -68 - 0K 16K CPU7 7 9:09 100.00% irq256: > bce0 >> 13 root 1 171 ki31 0K 16K CPU5 5 123:49 99.07% idle: cpu5 >> 40 root 1 -68 - 0K 16K WAIT 0 4:40 51.17% irq257: > bce1 >> 18 root 1 171 ki31 0K 16K RUN 0 117:48 49.37% idle: cpu0 >> 11 root 1 171 ki31 0K 16K RUN 7 115:25 0.00% idle: cpu7 >> 19 root 1 -32 - 0K 16K WAIT 0 0:39 0.00% swi4: > clock s >> 14367 root 1 44 0 5176K 3104K select 2 0:01 0.00% dhcpd >> 22 root 1 -16 - 0K 16K - 3 0:01 0.00% yarrow >> 25 root 1 -24 - 0K 16K WAIT 0 0:00 0.00% swi6: > Giant t >> 11658 root 1 44 0 32936K 4540K select 1 0:00 0.00% sshd >> 14224 root 1 44 0 32936K 4540K select 5 0:00 0.00% sshd >> 41 root 1 -60 - 0K 16K WAIT 0 0:00 0.00% irq1: > atkbd0 >> 4 root 1 -8 - 0K 16K - 2 0:00 0.00% g_down >> >> The bce0 interface interrupt (irq256) gets stressed out which already >> have 100% of CPU7 while CPU0 is around 51.17%. Any more >> recommendations? Is there anything we can do about optimization with >> MSI? > > Well, on 7.x you can try turning net.isr.direct off (sysctl). However, it > seems you are hammering your bce0 interface. You might want to try using > polling on bce0 and seeing if it keeps up with the traffic better. > > -- > John Baldwin > With net.isr.direct=0, my IBM system lessens CPU utilization per interface (bce0 and bce1) but swi1:net increase its utilization. Can you explained what's happening here? What does net.isr.direct do with the decrease of CPU utilization on its interface? I really wanted to know what happened internally during the packets being processed and received by the interfaces then to the device interrupt up to the software interrupt level because I am confused when enabling/disabling net.isr.direct in sysctl. Is there a tool that can we used to trace this process just to be able to know which part of the kernel internal is doing the bottleneck especially when net.isr.direct=1? By the way with device polling enabled, the system experienced packet errors and the interface throughput is worst, so I avoid using it though. PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND 16 root 1 171 ki31 0K 16K CPU10 a 86:06 89.06% idle: cpu10 27 root 1 -44 - 0K 16K CPU1 1 34:37 82.67% swi1: net 52 root 1 -68 - 0K 16K WAIT b 51:59 59.77% irq32: bce1 15 root 1 171 ki31 0K 16K RUN b 69:28 43.16% idle: cpu11 25 root 1 171 ki31 0K 16K RUN 1 115:35 24.27% idle: cpu1 51 root 1 -68 - 0K 16K CPU10 a 35:21 13.48% irq31: bce0 Regards, Archimedes