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From: Peter Zijlstra <peterz@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Waiman Long <waiman.long@hp.com>,
	arnd@arndb.de, linux-arch@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, rostedt@goodmis.org,
	akpm@linux-foundation.org, walken@google.com,
	andi@firstfloor.org, riel@redhat.com, paulmck@linux.vnet.ibm.com,
	torvalds@linux-foundation.org, oleg@redhat.com
Subject: Re: [RFC][PATCH 0/7] locking: qspinlock
Date: Wed, 12 Mar 2014 07:15:03 +0100	[thread overview]
Message-ID: <20140312061503.GH30956@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140312023153.GW13647@dastard>

On Wed, Mar 12, 2014 at 01:31:53PM +1100, Dave Chinner wrote:
> With the queuing spinlock, I expected to see somewhat better
> results, but I didn't at first. Turns out if you have any sort of
> lock debugging turned on, then the code doesn't ever go into the
> lock slow path and hence does not ever enter the "lock failed" slow
> path where all the contention fixes are supposed to be.

Yeah; its a 'feature' of the spinlock debugging to turn all spinlocks
into test-and-set thingies.

> Anyway, with all lock debugging turned off, the system hangs
> the instant I start the multithreaded bulkstat workload. Even the
> console is unrepsonsive. 

Oops, I only briefly tested this series in userspace and that seemed to
work. I'll go prod at it. Thanks for having a look though.

Is that bstat test any easier/faster to setup/run than the aim7 crap?

  parent reply	other threads:[~2014-03-12  6:15 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-10 15:42 [RFC][PATCH 0/7] locking: qspinlock Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 1/7] qspinlock: Introducing a 4-byte queue spinlock implementation Peter Zijlstra
2014-03-13 13:07   ` Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 2/7] qspinlock, x86: Enable x86 to use queue spinlock Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 3/7] qspinlock: Add pending bit Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 4/7] x86: Add atomic_test_and_set_bit() Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 5/7] qspinlock: Optimize the pending case Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 6/7] qspinlock: Optimize xchg_tail Peter Zijlstra
2014-03-10 15:42 ` [RFC][PATCH 7/7] qspinlock: Optimize for smaller NR_CPUS Peter Zijlstra
2014-03-11 10:45 ` [RFC][PATCH 0/7] locking: qspinlock Ingo Molnar
2014-03-11 11:02   ` Peter Zijlstra
2014-03-11 11:04     ` Ingo Molnar
2014-03-12  3:17   ` Waiman Long
2014-03-12  6:24     ` Peter Zijlstra
2014-03-12 15:32       ` Peter Zijlstra
2014-03-12 19:00       ` Waiman Long
2014-03-12  2:31 ` Dave Chinner
2014-03-12  3:11   ` Steven Rostedt
2014-03-12  4:26     ` Dave Chinner
2014-03-12 10:07       ` Steven Rostedt
2014-03-12 15:57         ` Peter Zijlstra
2014-03-12 16:06           ` Linus Torvalds
2014-03-12 16:19           ` Steven Rostedt
2014-03-12 16:23             ` Peter Zijlstra
2014-03-12  6:15   ` Peter Zijlstra [this message]
2014-03-12 23:48     ` Dave Chinner

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