Date: Mon, 6 Mar 2006 13:52:03 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-arch@freebsd.org Cc: arch@freebsd.org, Poul-Henning Kamp <phk@phk.freebsd.dk> Subject: Re: wakeup idea... Message-ID: <200603061352.05452.jhb@freebsd.org> In-Reply-To: <35339.1141557488@critter.freebsd.dk> References: <35339.1141557488@critter.freebsd.dk>
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On Sunday 05 March 2006 06:18, Poul-Henning Kamp wrote:
>
> Here is a possibly stupid idea.
>
> Historically sleep/wakeup have happened on a pointer which was just
> a magic number.
>
> In many cases, this pointer is actually a relevant datastructure.
>
> Would it possibly be an optimization to make a variant of the
> sleep/wakeup calls where the pointer points to an integer type which
> contains non-zero if anybody is actually sleeping on that address ?
>
> Anybody up for a quick prototype ?
It lives in sys/kern/kern_condvar.c
void
cv_signal(struct cv *cvp)
{
sleepq_lock(cvp);
if (cvp->cv_waiters > 0) {
cvp->cv_waiters--;
sleepq_signal(cvp, SLEEPQ_CONDVAR, -1);
} else
sleepq_release(cvp);
}
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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