From owner-soc-status@FreeBSD.ORG Fri Mar 14 19:05:31 2014 Return-Path: Delivered-To: soc-status@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2AEA721B; Fri, 14 Mar 2014 19:05:31 +0000 (UTC) Received: from freebsd.czest.pl (freebsd.czest.pl [212.87.224.105]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 92209166; Fri, 14 Mar 2014 19:05:30 +0000 (UTC) Received: from freebsd.czest.pl (freebsd.czest.pl [212.87.224.105]) by freebsd.czest.pl (8.14.5/8.14.5) with ESMTP id s2EJ3rZr046389; Fri, 14 Mar 2014 19:03:53 GMT (envelope-from wkoszek@freebsd.czest.pl) Received: (from wkoszek@localhost) by freebsd.czest.pl (8.14.5/8.14.5/Submit) id s2EJ3rR8046388; Fri, 14 Mar 2014 19:03:53 GMT (envelope-from wkoszek) Date: Fri, 14 Mar 2014 19:03:53 +0000 From: "Wojciech A. Koszek" To: yan cui Subject: Re: FreeBSD GSOC proposal in 2014 Message-ID: <20140314190353.GC37327@FreeBSD.org> References: <20140314070218.GA37327@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Status: No, score=-0.4 required=5.0 tests=RP_MATCHES_RCVD, SPF_HELO_PASS, SPF_PASS autolearn=ham version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on freebsd.czest.pl X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (freebsd.czest.pl [212.87.224.105]); Fri, 14 Mar 2014 19:03:57 +0000 (UTC) Cc: freebsd-hackers@freebsd.org, freebsd-current@freebsd.org, soc-status@freebsd.org X-BeenThere: soc-status@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Summer of Code Status Reports and Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Mar 2014 19:05:31 -0000 On Fri, Mar 14, 2014 at 01:07:48PM -0400, yan cui wrote: > Thanks for the reply! I will get more information about KTR subsystem. > You can also look here: http://people.freebsd.org/~kris/scaling/Help_my_system_is_slow.pdf Wojciech > > > > > 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. > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" -- Wojciech A. Koszek wkoszek@FreeBSD.czest.pl http://FreeBSD.czest.pl/~wkoszek/