Thanks for the reply! I will get more information about KTR subsystem.
2014-03-14 3:02 GMT-04:00 Wojciech A. Koszek <wkos...@freebsd.org>: > 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 <ccuiy...@gmail.com>: > > > > > 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 <ccuiy...@gmail.com>: > > > > > > 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-sta...@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/soc-status > > To unsubscribe, send any mail to "soc-status-unsubscr...@freebsd.org" > > -- > Wojciech A. Koszek > wkos...@freebsd.czest.pl > http://FreeBSD.czest.pl/~wkoszek/ > -- Think big; Dream impossible; Make it happen. _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"