From: David Howells <dhowells@redhat.com>
To: Nicolas Pitre <nico@cam.org>
Cc: dhowells@redhat.com,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-kernel@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org>,
benh@kernel.crashing.org, paulus@samba.org,
David Miller <davem@davemloft.net>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
linux-arch@vger.kernel.org
Subject: Re: [RFC patch 08/18] cnt32_to_63 should use smp_rmb()
Date: Fri, 07 Nov 2008 23:55:05 +0000 [thread overview]
Message-ID: <9500.1226102105@redhat.com> (raw)
In-Reply-To: <alpine.LFD.2.00.0811071513180.13034@xanadu.home>
Nicolas Pitre <nico@cam.org> wrote:
> I explained several times already why I disagree. Preemption is not a
> problem unless you're preempted away for long enough, or IOW if your
> counter is too fast.
That's my point. Say a nice -19 process gets preempted... what guarantees
that it will resume within, the time it takes the counter to wrap? Even if
the preempting process goes back to sleep, in that time a bunch of other
processes could have woken up and could starve it for a long period of time.
David
next prev parent reply other threads:[~2008-11-07 23:56 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-07 5:23 [RFC patch 00/18] Trace Clock v2 Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 01/18] get_cycles() : kconfig HAVE_GET_CYCLES Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 02/18] get_cycles() : x86 HAVE_GET_CYCLES Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 03/18] get_cycles() : sparc64 HAVE_GET_CYCLES Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 04/18] get_cycles() : powerpc64 HAVE_GET_CYCLES Mathieu Desnoyers
2008-11-07 14:56 ` Josh Boyer
2008-11-07 18:14 ` Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 05/18] get_cycles() : MIPS HAVE_GET_CYCLES_32 Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 06/18] Trace clock generic Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 07/18] Trace clock core Mathieu Desnoyers
2008-11-07 5:52 ` Andrew Morton
2008-11-07 6:16 ` Mathieu Desnoyers
2008-11-07 6:26 ` Andrew Morton
2008-11-07 16:12 ` Mathieu Desnoyers
2008-11-07 16:19 ` Andrew Morton
2008-11-07 18:16 ` Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 08/18] cnt32_to_63 should use smp_rmb() Mathieu Desnoyers
2008-11-07 6:05 ` Andrew Morton
2008-11-07 8:12 ` Nicolas Pitre
2008-11-07 8:38 ` Andrew Morton
2008-11-07 11:20 ` David Howells
2008-11-07 15:01 ` Nicolas Pitre
2008-11-07 15:50 ` Andrew Morton
2008-11-07 16:21 ` David Howells
2008-11-07 16:29 ` Andrew Morton
2008-11-07 17:10 ` David Howells
2008-11-07 17:26 ` Andrew Morton
2008-11-07 18:00 ` Mathieu Desnoyers
2008-11-07 18:21 ` Andrew Morton
2008-11-07 18:30 ` Harvey Harrison
2008-11-07 18:42 ` Mathieu Desnoyers
2008-11-07 18:33 ` Mathieu Desnoyers
2008-11-07 18:36 ` Linus Torvalds
2008-11-07 18:45 ` Andrew Morton
2008-11-07 16:47 ` Nicolas Pitre
2008-11-07 16:55 ` David Howells
2008-11-07 17:21 ` Andrew Morton
2008-11-07 20:03 ` Nicolas Pitre
2008-11-07 16:07 ` David Howells
2008-11-07 16:47 ` Mathieu Desnoyers
2008-11-07 17:04 ` David Howells
2008-11-07 17:17 ` Mathieu Desnoyers
2008-11-07 23:27 ` David Howells
2008-11-07 20:11 ` Russell King
2008-11-07 21:36 ` Mathieu Desnoyers
2008-11-07 21:36 ` Mathieu Desnoyers
2008-11-07 22:18 ` Russell King
2008-11-07 22:36 ` Mathieu Desnoyers
2008-11-07 22:36 ` Mathieu Desnoyers
2008-11-07 23:41 ` David Howells
2008-11-08 0:15 ` Russell King
2008-11-08 0:45 ` David Howells
2008-11-08 15:24 ` Nicolas Pitre
2008-11-08 23:20 ` [PATCH] clarify usage expectations for cnt32_to_63() Nicolas Pitre
2008-11-09 2:25 ` Mathieu Desnoyers
2008-11-09 2:54 ` Nicolas Pitre
2008-11-09 5:06 ` Nicolas Pitre
2008-11-09 5:27 ` [PATCH v2] " Nicolas Pitre
2008-11-09 6:48 ` Mathieu Desnoyers
2008-11-09 13:34 ` Nicolas Pitre
2008-11-09 13:43 ` Russell King
2008-11-09 16:22 ` Mathieu Desnoyers
2008-11-10 4:20 ` Nicolas Pitre
2008-11-10 4:42 ` Andrew Morton
2008-11-10 21:34 ` Nicolas Pitre
2008-11-10 21:58 ` Andrew Morton
2008-11-10 23:15 ` Nicolas Pitre
2008-11-10 23:22 ` Andrew Morton
2008-11-10 23:38 ` Steven Rostedt
2008-11-11 0:26 ` Nicolas Pitre
2008-11-11 18:28 ` [PATCH] convert cnt32_to_63 to inline Mathieu Desnoyers
2008-11-11 19:13 ` Russell King
2008-11-11 20:11 ` Mathieu Desnoyers
2008-11-11 20:11 ` Mathieu Desnoyers
2008-11-11 21:51 ` Russell King
2008-11-12 3:48 ` Mathieu Desnoyers
2008-11-12 3:48 ` Mathieu Desnoyers
2008-11-11 21:00 ` Nicolas Pitre
2008-11-11 21:13 ` Russell King
2008-11-11 22:31 ` David Howells
2008-11-11 22:37 ` Peter Zijlstra
2008-11-12 1:13 ` Steven Rostedt
2008-11-07 11:03 ` [RFC patch 08/18] cnt32_to_63 should use smp_rmb() David Howells
2008-11-07 16:51 ` Mathieu Desnoyers
2008-11-07 20:18 ` Nicolas Pitre
2008-11-07 23:55 ` David Howells [this message]
2008-11-07 10:59 ` David Howells
2008-11-07 10:55 ` David Howells
2008-11-07 17:09 ` Mathieu Desnoyers
2008-11-07 17:33 ` Steven Rostedt
2008-11-07 19:18 ` Mathieu Desnoyers
2008-11-07 19:32 ` Peter Zijlstra
2008-11-07 20:02 ` Mathieu Desnoyers
2008-11-07 20:45 ` Mathieu Desnoyers
2008-11-07 20:54 ` Paul E. McKenney
2008-11-07 21:04 ` Steven Rostedt
2008-11-08 0:34 ` Paul E. McKenney
2008-11-07 21:16 ` Mathieu Desnoyers
2008-11-07 23:50 ` David Howells
2008-11-08 0:55 ` Steven Rostedt
2008-11-09 11:51 ` David Howells
2008-11-09 14:31 ` Steven Rostedt
2008-11-09 16:18 ` Mathieu Desnoyers
2008-11-07 20:08 ` Steven Rostedt
2008-11-07 20:55 ` Paul E. McKenney
2008-11-07 21:27 ` Mathieu Desnoyers
2008-11-07 20:36 ` Nicolas Pitre
2008-11-07 20:55 ` Mathieu Desnoyers
2008-11-07 21:22 ` Nicolas Pitre
2008-11-07 5:23 ` [RFC patch 09/18] Powerpc : Trace clock Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 10/18] Sparc64 " Mathieu Desnoyers
2008-11-07 5:45 ` David Miller
2008-11-07 5:23 ` [RFC patch 11/18] LTTng timestamp sh Mathieu Desnoyers
2008-11-07 5:23 ` Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 12/18] LTTng - TSC synchronicity test Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 13/18] x86 : remove arch-specific tsc_sync.c Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 14/18] MIPS use tsc_sync.c Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 15/18] MIPS : export hpt frequency for trace_clock Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 16/18] MIPS create empty sync_core() Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 17/18] MIPS : Trace clock Mathieu Desnoyers
2008-11-07 11:53 ` Peter Zijlstra
2008-11-07 17:44 ` Mathieu Desnoyers
2008-11-07 5:23 ` [RFC patch 18/18] x86 trace clock Mathieu Desnoyers
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