From: Arjan van de Ven <arjanv@redhat.com>
To: george anzinger <george@mvista.com>
Cc: Arjan van de Ven <arjanv@redhat.com>,
Linus Torvalds <torvalds@transmeta.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] High-res-timers part 1 (core) take 20
Date: Mon, 9 Dec 2002 07:34:34 -0500 [thread overview]
Message-ID: <20021209073434.A24382@devserv.devel.redhat.com> (raw)
In-Reply-To: <3DF48C4C.3F056661@mvista.com>; from george@mvista.com on Mon, Dec 09, 2002 at 04:27:56AM -0800
On Mon, Dec 09, 2002 at 04:27:56AM -0800, george anzinger wrote:
> >
> > that's why spinlocks are effectively nops on UP.
> > What you say is true of just about every spinlock user, and no
> > they shouldn't all do some IF_SMP() thing; the spinlock itself should be
> > (and is) zero on UP
>
> But with preemption, they really are not nops on UP...
that doesn't justify fuglyfying the kernel code. If you can't live
with the overhead of preemption, disable preemption. Simple.
We DON'T want
spin_lock_nop_on_preempt()
...
spin_unlock_nop_on_preempt()
really, I don't, and I can't see anyone else wanting that either
next prev parent reply other threads:[~2002-12-09 12:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-08 7:46 [PATCH 1/3] High-res-timers part 1 (core) take 20 george anzinger
2002-12-08 9:50 ` Arjan van de Ven
2002-12-09 7:03 ` george anzinger
2002-12-09 8:21 ` Robert Love
2002-12-09 8:53 ` Arjan van de Ven
2002-12-09 12:27 ` george anzinger
2002-12-09 12:34 ` Arjan van de Ven [this message]
2002-12-10 6:55 ` george anzinger
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