From: Andrew Morton <akpm@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Gregory Haskins <ghaskins@novell.com>,
a.p.zijlstra@chello.nl, tglx@linutronix.de, rostedt@goodmis.org,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
bill.huey@gmail.com, kevin@hilman.org, cminyard@mvista.com,
dsingleton@mvista.com, dwalker@mvista.com, npiggin@suse.de,
dsaxena@plexity.net, ak@suse.de, gregkh@suse.de,
sdietrich@novell.com, pmorreale@novell.com, mkohari@novell.com
Subject: Re: [PATCH [RT] 00/14] RFC - adaptive real-time locks
Date: Sat, 23 Feb 2008 00:03:45 -0800 [thread overview]
Message-ID: <20080223000345.e6be3280.akpm@linux-foundation.org> (raw)
In-Reply-To: <20080221212420.GA20953@elte.hu>
On Thu, 21 Feb 2008 22:24:20 +0100 Ingo Molnar <mingo@elte.hu> wrote:
> regarding the concept: adaptive mutexes have been talked about in the
> past, but their advantage is not at all clear, that's why we havent done
> them. It's definitely not an unambigiously win-win concept.
When ext3 was converted from sleeping locks to spinlocks, dbench-on-numaq
throughput went up by a factor of ten. I'd expect that what RT has done
was a truly awful change for lots of workloads on lots of machines.
Yeah, there's the dont-enable-it-if-you're-doing-that option, but that adds
the we-just-doubled-the-number-of-kernels-distros-need-to-ship problem.
Does -rt also make bit_spin_lock preemptible? If not, I'd have thought the
change was of little benefit to ext3/jbd and it might as well go back to
spinning locks.
prev parent reply other threads:[~2008-02-23 8:05 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-21 15:26 [PATCH [RT] 00/14] RFC - adaptive real-time locks Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 01/14] spinlocks: fix preemption feature when PREEMPT_RT is enabled Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 02/14] spinlock: make preemptible-waiter feature a specific config option Gregory Haskins
2008-02-22 19:09 ` Pavel Machek
2008-02-21 15:26 ` [PATCH [RT] 03/14] x86: FIFO ticket spinlocks Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 04/14] disable PREEMPT_SPINLOCK_WAITERS when x86 ticket/fifo spins are in use Gregory Haskins
2008-02-21 15:26 ` [PATCH [RT] 05/14] rearrange rt_spin_lock sleep Gregory Haskins
2008-02-22 13:29 ` Gregory Haskins
2008-02-22 13:35 ` Steven Rostedt
2008-02-22 13:40 ` Peter Zijlstra
2008-02-22 13:35 ` Ingo Molnar
2008-02-22 13:43 ` Steven Rostedt
2008-02-22 13:46 ` Steven Rostedt
2008-02-21 15:26 ` [PATCH [RT] 06/14] optimize rt lock wakeup Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 07/14] adaptive real-time lock support Gregory Haskins
2008-02-22 19:14 ` Pavel Machek
2008-02-21 15:27 ` [PATCH [RT] 08/14] add a loop counter based timeout mechanism Gregory Haskins
2008-02-21 16:41 ` Andi Kleen
2008-02-21 17:02 ` Gregory Haskins
2008-02-21 17:04 ` Peter W. Morreale
2008-02-21 17:06 ` Sven-Thorsten Dietrich
2008-02-22 19:08 ` Paul E. McKenney
2008-02-22 19:19 ` Bill Huey (hui)
2008-02-22 19:21 ` Bill Huey (hui)
2008-02-22 19:43 ` Paul E. McKenney
2008-02-22 19:55 ` Sven-Thorsten Dietrich
2008-02-22 20:23 ` Paul E. McKenney
2008-02-22 22:03 ` Gregory Haskins
2008-02-23 12:31 ` Andi Kleen
2008-02-23 16:32 ` Paul E. McKenney
2008-02-25 23:52 ` Sven-Thorsten Dietrich
2008-02-22 20:36 ` Peter W. Morreale
2008-02-23 7:36 ` Sven-Thorsten Dietrich
2008-02-22 20:15 ` Peter W. Morreale
2008-02-21 15:27 ` [PATCH [RT] 09/14] adaptive mutexes Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 10/14] adjust pi_lock usage in wakeup Gregory Haskins
2008-02-21 16:48 ` Steven Rostedt
2008-02-21 17:09 ` Peter W. Morreale
2008-02-21 15:27 ` [PATCH [RT] 11/14] optimize the !printk fastpath through the lock acquisition Gregory Haskins
2008-02-21 16:36 ` Andi Kleen
2008-02-21 16:47 ` Gregory Haskins
2008-02-22 19:18 ` Pavel Machek
2008-02-22 22:20 ` Gregory Haskins
2008-02-23 0:43 ` Bill Huey (hui)
2008-02-25 5:20 ` Gregory Haskins
2008-02-25 6:21 ` Bill Huey (hui)
2008-02-25 9:02 ` Bill Huey (hui)
2008-02-21 15:27 ` [PATCH [RT] 12/14] remove the extra call to try_to_take_lock Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 13/14] allow rt-mutex lock-stealing to include lateral priority Gregory Haskins
2008-02-21 15:27 ` [PATCH [RT] 14/14] sysctl for runtime-control of lateral mutex stealing Gregory Haskins
2008-02-21 16:05 ` [PATCH [RT] 00/14] RFC - adaptive real-time locks Gregory Haskins
2008-02-21 21:24 ` Ingo Molnar
2008-02-21 21:33 ` Bill Huey (hui)
[not found] ` <20080221214219.GA27209@elte.hu>
2008-02-21 21:56 ` Gregory Haskins
2008-02-21 22:53 ` Bill Huey (hui)
2008-02-21 21:40 ` Gregory Haskins
2008-02-21 22:12 ` Peter W. Morreale
2008-02-21 22:42 ` Peter W. Morreale
2008-02-23 8:03 ` Andrew Morton [this message]
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