From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Clark Williams <williams@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC PATCH RT] rwsem: The return of multi-reader PI rwsems
Date: Thu, 10 Apr 2014 17:03:36 +0200 [thread overview]
Message-ID: <5346B2C8.6000207@linutronix.de> (raw)
In-Reply-To: <20140410094430.56ca9ee1@sluggy.gateway.2wire.net>
On 04/10/2014 04:44 PM, Clark Williams wrote:
> The means of each group of five test runs are:
>
> vanilla.log: 1210117 rt.log: 17210953 (14.2 x slower than
> vanilla) rt-fixes.log: 10062027 (8.3 x slower than vanilla)
> rt-multi.log: 3179582 (2.x x slower than vanilla)
>
>
> As expected, vanilla kicked RT's butt when hammering on the
> mmap_sem. But somewhat unexpectedly, your fixups helped quite a
> bit and the multi+fixups got RT back into being almost
> respectable.
>
> Obviously these are just preliminary results on one piece of h/w
> but it looks promising.
Is it easy to look at the latency when you have multiple readers and
and a high prio writer which has to boost all those readers away
instead just one?
Or is this something that should not happen for a high prio RT task
because it has all memory already allocated?
>
> Clark
Sebastian
next prev parent reply other threads:[~2014-04-10 15:03 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-09 19:19 [RFC PATCH RT] rwsem: The return of multi-reader PI rwsems Steven Rostedt
2014-04-10 14:18 ` Mike Galbraith
2014-04-10 14:28 ` Mike Galbraith
2014-04-10 14:32 ` Steven Rostedt
2014-04-11 2:50 ` Mike Galbraith
2014-04-11 3:25 ` Steven Rostedt
2014-04-11 3:52 ` Mike Galbraith
2014-04-11 4:25 ` Mike Galbraith
2014-04-10 14:44 ` Clark Williams
2014-04-10 15:01 ` Steven Rostedt
2014-04-10 15:03 ` Sebastian Andrzej Siewior [this message]
2014-04-10 15:36 ` Peter Zijlstra
2014-04-10 19:17 ` Steven Rostedt
2014-04-10 20:48 ` Peter Zijlstra
2014-04-10 21:30 ` Paul E. McKenney
2014-04-10 22:02 ` Steven Rostedt
2014-04-10 15:38 ` Steven Rostedt
2014-04-11 21:39 ` Daniel Bristot de Oliveira
2014-04-10 17:42 ` [RFC PATCH RT V2] " Steven Rostedt
2014-04-11 2:35 ` [RFC PATCH RT V3] " Steven Rostedt
2014-04-11 12:47 ` Carsten Emde
2014-04-11 13:25 ` Steven Rostedt
2014-04-17 23:26 ` [RFC PATCH RT V4] " Steven Rostedt
2014-04-18 8:19 ` Ingo Molnar
2014-04-24 17:52 ` Steven Rostedt
2014-04-14 9:55 ` [RFC PATCH RT] " Ingo Molnar
2014-04-14 13:34 ` Steven Rostedt
2014-04-14 14:08 ` Peter Zijlstra
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