From owner-freebsd-stable@FreeBSD.ORG Sun Apr 29 14:45:51 2012 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CAB56106566B; Sun, 29 Apr 2012 14:45:51 +0000 (UTC) (envelope-from oliver.pntr@gmail.com) Received: from mail-yw0-f54.google.com (mail-yw0-f54.google.com [209.85.213.54]) by mx1.freebsd.org (Postfix) with ESMTP id 572408FC14; Sun, 29 Apr 2012 14:45:51 +0000 (UTC) Received: by yhgm50 with SMTP id m50so1244187yhg.13 for ; Sun, 29 Apr 2012 07:45:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=Z1PeX4zzVhZc9QjABGRHfvFEBt91q3LffP509mxeGaw=; b=L3IGT9tEseWVYp7v5m2kRHRbg0Mj6MNf1ZcDUzSE8TsM96P4W9rrr7oqEdVQv4iDxJ iA1lS2FOz7pJSjGu5kjzf01zHyDJxZbaH2wU/Ui0KHUAq0HAORc/uFRMy8/pNDi169in z8LdUV57ykSFYlyAI7NyuY4vQbnweeV50FgB7njiSWq2EVLedOnjqhkqLlgl6s71k7Vj a6901p/XzIn643GUuuLVuWMZK9JYpM8WzX0vf754G1vJgXL+wJ3zn3rrq6U778eQFkIu /wO3rE2RKDU3cZ/py39ot8BEsftG52Rpx4iUI8vl9WwZ/XeMmL90NM4KD4po8Wg2ia5O oa0A== MIME-Version: 1.0 Received: by 10.236.173.6 with SMTP id u6mr8203971yhl.130.1335710750562; Sun, 29 Apr 2012 07:45:50 -0700 (PDT) Received: by 10.236.161.97 with HTTP; Sun, 29 Apr 2012 07:45:50 -0700 (PDT) In-Reply-To: <4F9D3B1F.2030208@FreeBSD.org> References: <20120427203013.GB60961@pcjas.obspm.fr> <20120427213459.GA61125@pcjas.obspm.fr> <4F9B946D.3030607@FreeBSD.org> <4F9CCEF2.6050609@FreeBSD.org> <20120429155512.M91148@sola.nimnet.asn.au> <4F9CDE91.1060300@FreeBSD.org> <4F9D2F0C.4050501@FreeBSD.org> <4F9D3B1F.2030208@FreeBSD.org> Date: Sun, 29 Apr 2012 16:45:50 +0200 Message-ID: From: Oliver Pinter To: Alexander Motin Content-Type: text/plain; charset=ISO-8859-1 Cc: Davide Italiano , Albert Shih , Luigi Rizzo , freebsd-stable@freebsd.org, Ian Smith Subject: Re: High load event idl. X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Apr 2012 14:45:51 -0000 On 4/29/12, Alexander Motin wrote: > On 04/29/12 15:27, Oliver Pinter wrote: >> http://oliverp.teteny.bme.hu/freebsd/ktr/ > > OK. Now there is no dummynet, but I've found there two more things: > 1. for some reason some acpi_thremal thread seems to consume about > 0.37s of time every 10s. I have no idea what is this. It's not 0.7 load, > but still strange at least. > 2. I suspect another possible synchronization between ehci driver and > loadavg as result of interrupt sharing between HPET timer used for time > events and EHCI USB hardware. Not sure what to do about this. Please > send _verbose_ dmesg to check whether this interrupt sharing is > unavoidable. > >> On 4/29/12, Alexander Motin wrote: >>> On 04/29/12 15:04, Oliver Pinter wrote: >>>> Removing dummynet from kernel don't chanage anything, that is releated >>>> to load average. The loadavg hold to 0.70 +/- 0.2. (single user : sh + >>>> top) >>> >>> New ktr dump? >>> >>>> On 4/29/12, Alexander Motin wrote: >>>>> On 04/29/12 09:09, Ian Smith wrote: >>>>>> On Sun, 29 Apr 2012 08:17:38 +0300, Alexander Motin wrote: >>>>>> > On 04/29/12 01:53, Oliver Pinter wrote: >>>>>> > > Attached the ktr file. This is on core2duo P9400 cpu ( >>>>>> > > smbios.system.product="HP ProBook 5310m (WD792EA#ABU)" >>>>>> ). >>>>>> The >>>>>> workload >>>>>> > > is only a single user boost: sh + top running, but the >>>>>> load >>>>>> average is >>>>>> > > near 0.5. >>>>>> > >>>>>> > ktr shows no real load there. But it shows that you are >>>>>> using >>>>>> dummynet, that >>>>>> > schedules its runs on every hardclock tick. I believe that >>>>>> load >>>>>> you >>>>>> see is >>>>>> > the result or synchronization between dummynet calls and >>>>>> loadvg >>>>>> sampling, >>>>>> > both of which called from hardclock. I think removing >>>>>> dummynet >>>>>> from >>>>>> equation, >>>>>> > should hide this problem and also reduce you laptops power >>>>>> consumption. >>>>>> > >>>>>> > What's about fixing this, it is loadavg sampling algorithm >>>>>> that >>>>>> should be >>>>>> > changed. Fixing dummynet to not run on every hardclock tick >>>>>> would >>>>>> also be >>>>>> > great. >>>>>> >>>>>> Wading in out of my depth, and copying Luigi in case he misses it .. >>>>>> but >>>>>> even back in the olden days when HZ defaulted to 100, one was advised >>>>>> to >>>>>> use HZ>= 1000 for smooth dummynet traffic shaping dispatch >>>>>> scheduling. >>>>>> >>>>>> I wonder, with the newer clocks and timers, whether there is another >>>>>> clock that could be used for dummynet scheduling, that would not have >>>>>> this effect (even if largely cosmetic?) on load average calculation? >>>>> >>>>> First of all, the easiest solution would be to make dummynet to >>>>> schedule >>>>> callout not automatically, but on first queued packet. I believe that >>>>> in >>>>> case of laptop the queue should be empty most of time and the callout >>>>> calls are completely useless there. Luigi promised to look on this >>>>> once. >>>>> >>>>> What's about better precision/removing synchronization -- there is >>>>> starting GSoC project now (by davide@) to rewrite callout(9) subsystem >>>>> to use better precision allowed by new timer drivers. While now it is >>>>> possible to get raw access to additional timer hardware available on >>>>> some systems, I don't think it is a good idea. http://freebsd.1045724.n5.nabble.com/amd64-160419-acpi-thermal-kernel-thread-high-CPU-usage-td4765266.html but this "high cpu load" is gone, releated to acpi_thermal in 2011 september > > > -- > Alexander Motin >