Date: Tue, 27 Jun 2006 11:27:12 -0400 From: John Baldwin <jhb@freebsd.org> To: Kip Macy <kmacy@freebsd.org> Cc: kris@freebsd.org, Perforce Change Reviews <perforce@freebsd.org> Subject: Re: PERFORCE change 100121 for review Message-ID: <200606271127.13228.jhb@freebsd.org> In-Reply-To: <200606270742.k5R7gCfT001310@repoman.freebsd.org> References: <200606270742.k5R7gCfT001310@repoman.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tuesday 27 June 2006 03:42, Kip Macy wrote: > http://perforce.freebsd.org/chv.cgi?CH=100121 > > Change 100121 by kmacy@kmacy_storage:sun4v_work_sleepq on 2006/06/27 07:41:14 > > avoid pointless turnstile contention if mutex owner is running Yes, I did this already in jhb_lock for both mutexes and rwlocks at BSDCan. Kris said my patch panic'd for him at BSDCan but I don't have an SMP machine I can test it on now to debug it. :( > > Affected files ... > > .. //depot/projects/kmacy_sun4v/src/sys/kern/kern_mutex.c#20 edit > > Differences ... > > ==== //depot/projects/kmacy_sun4v/src/sys/kern/kern_mutex.c#20 (text+ko) ==== > > @@ -176,7 +176,7 @@ > static int mutex_prof_maxrecords = MPROF_HASH_SIZE; > SYSCTL_INT(_debug_mutex_prof, OID_AUTO, maxrecords, CTLFLAG_RD, > &mutex_prof_maxrecords, 0, "Maximum number of profiling records"); > -int mutex_prof_rejected; > +int mutex_prof_rejected = 0; > SYSCTL_INT(_debug_mutex_prof, OID_AUTO, rejected, CTLFLAG_RD, > &mutex_prof_rejected, 0, "Number of rejected profiling records"); > static int mutex_prof_hashsize = MPROF_HASH_SIZE; > @@ -418,6 +418,16 @@ > > while (!_obtain_lock(m, tid)) { > lock_profile_obtain_lock_failed(&m->mtx_object, &contested); > +#if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) > + /* > + * If the current owner of the lock is executing on another > + * CPU, spin instead of blocking. > + */ > + for (owner = mtx_owner(m); owner && TD_IS_RUNNING(owner); owner = mtx_owner(m)) > + cpu_spinwait(); > + if (mtx_unowned(m)) > + continue; > +#endif /* SMP && !NO_ADAPTIVE_MUTEXES */ > turnstile_lock(&m->mtx_object); > v = m->mtx_lock; > > @@ -425,7 +435,7 @@ > * Check if the lock has been released while spinning for > * the turnstile chain lock. > */ > - if (v == MTX_UNOWNED) { > + if (mtx_unowned(m)) { > turnstile_release(&m->mtx_object); > cpu_spinwait(); > continue; > @@ -837,6 +847,8 @@ > mtx_validate(m); > #endif > > + > + > /* Determine lock class and lock flags. */ > if (opts & MTX_SPIN) > class = &lock_class_mtx_spin; > -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200606271127.13228.jhb>