Date: Tue, 27 Sep 2005 19:17:49 +1000 From: Peter Jeremy <PeterJeremy@optushome.com.au> To: Kris Kennaway <kris@obsecurity.org> Cc: freebsd-current@freebsd.org Subject: Re: 4BSD/ULE numbers... Message-ID: <20050927091749.GT40237@cirb503493.alcatel.com.au> In-Reply-To: <20050926224453.GB39901@xor.obsecurity.org> References: <200509261847.35558@harrymail> <20050926174738.GA57284@xor.obsecurity.org> <43387811.1090308@freebsd.org> <20050926224453.GB39901@xor.obsecurity.org>
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On Mon, 2005-Sep-26 18:44:53 -0400, Kris Kennaway wrote: >I'd love a way to measure sched_lock contention..I'm sure it's a >factor on e.g. my machines with >=10 CPUs, but mutex profiling doesn't >see it because it's a spinlock. How about adding a spincount field in struct mtx and incrementing it in the inner loop of _mtx_lock_spin()? This wouldn't be perfect but you could get a rough idea of the lock contention by looking at the rate that the spincount field incremented. Working out how many CPUs are simultaneously contending for sched_lock would be more difficult but doable. -- Peter Jeremy
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