Date: Thu, 15 Jan 2009 15:18:33 -0500 From: John Baldwin <jhb@freebsd.org> To: src-committers@freebsd.org Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org Subject: Re: svn commit: r187156 - head/tools/sched Message-ID: <200901151518.34220.jhb@freebsd.org> In-Reply-To: <200901131644.n0DGiI9L009063@svn.freebsd.org> References: <200901131644.n0DGiI9L009063@svn.freebsd.org>
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On Tuesday 13 January 2009 11:44:18 am John Baldwin wrote: > Author: jhb > Date: Tue Jan 13 16:44:18 2009 > New Revision: 187156 > URL: http://svn.freebsd.org/changeset/base/187156 > > Log: > Add support for two new event source types: > - Callwheels traced via KTR_CALLOUT. Each CPU is assigned a callwheel > source. The events on this source are the execution of individual callout > routines. Each routine shows up as a green rectangle while it is executed > and the event details include the function pointer and argument. > - Locks traced via KTR_LOCK. Currently, each lock name is assigned an event > source (since the existing KTR_LOCK traces only include lock names and > not pointers). This does mean that if multiple locks of the same name are > manipulated, the source line for that name may be confusing. However, for > many cases this can be useful. Locks are blue when they are held and > purple when contested. The contention support is a bit weak due to > limitations in the rw_rlock() and mtx_lock_spin() logging messages > currently. I also have not added support for contention on lockmgr, > sx, or rmlocks yet. What is there now can be profitably used to examine > activity on Giant however. > - Expand the width of the event source names column a bit to allow for some > of the longer names of these new source types. For some examples, check out www.freebsd.org/~jhb/sysctl_before.png and sysctl_after.png. Those are screenshots of 'sysctl -a' showing lock activity. In particular, in 'after' I removed (via #if 0) the debug.hashstat sysctls (from sys/kern/vfs_cache.c). In the 'before' graph one of those two sysctls (the raw dump of the hash table depths) took 7 milliseconds to run on my test machine (2 x 3.4 GHz Intel dual-core) holding Giant the entire time which caused softclock to block on Giant for a couple of milliseconds. (These traces were performed on 7-stable.) Once I get more caught up I plan on sticking those sysctl's under some sort of #ifdef that isn't on by default. -- John Baldwin
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