From owner-freebsd-current@FreeBSD.ORG Fri Mar 14 17:07:50 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 6053C648; Fri, 14 Mar 2014 17:07:50 +0000 (UTC) Received: from mail-yh0-x22a.google.com (mail-yh0-x22a.google.com [IPv6:2607:f8b0:4002:c01::22a]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id AC7D9381; Fri, 14 Mar 2014 17:07:49 +0000 (UTC) Received: by mail-yh0-f42.google.com with SMTP id t59so2895511yho.1 for ; Fri, 14 Mar 2014 10:07:49 -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=CprsYvtgBOfnvPAkw5Trhhbb+uB3mtkiX0mvV8u3Ii4=; b=O9NOGpQV2SKu+reO7zbvp7+TC/NOuORSuvMGSKaIiDQMKH4AB0b1v83e0oqWgAgOHL +wln8QN2qwyf1tp4R5dUJQYyqFvXTKByoOe/gHrZOrrnFmDuYv6Q0f3Pra2e+6KtYCqL rxCFGVscaox0ZXmmCRj+3o4agx1JtY1Bj3Rfpwe8l+sUq/y5B6g87tJ9H1/MywiA9Wxf cKBze6/mNaT1oNcDvAFPMqkEyzlqchE2UjCOljeRP6o/Shk/e9mNck3p5jzmnFmox88v T7n5rPBsourxdSKphY9o5CDhIcjyHSbJ5zgvZw6Etvb+GeEX1VP+6EjBVcxb+O/qkzD+ nDcQ== MIME-Version: 1.0 X-Received: by 10.236.177.100 with SMTP id c64mr4062029yhm.30.1394816868904; Fri, 14 Mar 2014 10:07:48 -0700 (PDT) Received: by 10.170.66.204 with HTTP; Fri, 14 Mar 2014 10:07:48 -0700 (PDT) In-Reply-To: <20140314070218.GA37327@FreeBSD.org> References: <20140314070218.GA37327@FreeBSD.org> Date: Fri, 14 Mar 2014 13:07:48 -0400 Message-ID: Subject: Re: FreeBSD GSOC proposal in 2014 From: yan cui To: "Wojciech A. Koszek" Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: freebsd-hackers@freebsd.org, freebsd-current@freebsd.org, soc-status@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Mar 2014 17:07:50 -0000 Thanks for the reply! I will get more information about KTR subsystem. 2014-03-14 3:02 GMT-04:00 Wojciech A. Koszek : > On Thu, Mar 13, 2014 at 09:56:35PM -0400, yan cui wrote: > > Hi all, > > > > I write this mail to make my question clear. I know witness can be > used > > to detect wrong lock order in the kernel. However, can it be used to do > > lock profiling (what I mean is to report the information such as which > > locks are most contended and print some related statistics such as > calling > > graph, etc)? > > In other words, is it enough to finish the task by porting witness to the > > pthread library? > > > > Yan, > > To my knowledge WITNESS is the only tool for lock order verification. > > For lock profiling in the FreeBSD kernel there's a KTR subsystem. KTR > mechanism is basically like syslog() in the user-space, but for the kernel. > KTR subsystem will receive messages from KTR API that is placed in the > FreeBSD kernel. Messages get stored on the list of some sort. List can be > exported to a file. File you can later analyze. > > Jeff wrote a Python app which can be used for pre-processing the KTR logs > from scheduler and protting them visually. Link: > > http://svnweb.freebsd.org/base/head/tools/sched/schedgraph.py > > Instead of porting witness to pthreads, maybe we could evaluate expanding > WITNESS to cover kern_umtx? This could prove to be more universal. > > Wojciech > > > > > 2014-03-13 19:19 GMT-04:00 yan cui : > > > > > Hi all, > > > > > > I have downloaded the newest FreeBSD-release kernel and scanned > some > > > codes. > > > Wonder to know whether the lock order verification and lock profiling > tool > > > mentioned in > > > the GSoC idea list is witness? Are there any other tools that needs to > > > look at in the FreeBSD kernel? > > > > > > Thanks, Yan > > > > > > > > > 2014-03-09 15:46 GMT-04:00 yan cui : > > > > > > Hi All, > > >> > > >> I am a student in Columbia University (Yan Cui), and want to join > > >> the FreeBSD GSOC 2014. After scanned the idea list posted online, I > think I > > >> am interested in > > >> the idea titled "user space pthread mutex lock contention profiling > and > > >> lock order verification tools". I have several year experiences in > kernel > > >> and user locking and believe I can complete the task in time. > Currently, I > > >> wonder to know, before submitting an application on GSOC home page, > do I > > >> need to submit some documents in the community (to review?) > > >> > > >> Best Wishes! > > >> Yan > > >> > > >> -- > > >> Think big; Dream impossible; Make it happen. > > >> > > > > > > > > > > > > -- > > > Think big; Dream impossible; Make it happen. > > > > > > > > > > > -- > > Think big; Dream impossible; Make it happen. > > _______________________________________________ > > soc-status@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/soc-status > > To unsubscribe, send any mail to "soc-status-unsubscribe@freebsd.org" > > -- > Wojciech A. Koszek > wkoszek@FreeBSD.czest.pl > http://FreeBSD.czest.pl/~wkoszek/ > -- Think big; Dream impossible; Make it happen.