From: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>,
tglx@linutronix.de, mingo@redhat.com, rostedt@goodmis.org,
cfriesen@nortel.com, oleg@redhat.com, fweisbec@gmail.com,
darren@dvhart.com, johan.eker@ericsson.com, p.faure@akatech.ch,
linux-kernel@vger.kernel.org, claudio@evidence.eu.com,
michael@amarulasolutions.com, fchecconi@gmail.com,
nicola.manica@disi.unitn.it, luca.abeni@unitn.it,
dhaval.giani@gmail.com, hgu1972@gmail.com,
paulmck@linux.vnet.ibm.com, raistlin@linux.it,
insop.song@ericsson.com, liming.wang@windriver.com
Subject: Re: [PATCH 05/16] sched: SCHED_DEADLINE policy implementation.
Date: Tue, 24 Apr 2012 00:21:21 +0100 [thread overview]
Message-ID: <4F95E3F1.3030407@sssup.it> (raw)
In-Reply-To: <1335218328.28150.181.camel@twins>
Il 23/04/2012 22:58, Peter Zijlstra ha scritto:
> On Mon, 2012-04-23 at 22:55 +0100, Tommaso Cucinotta wrote:
>> why not write this straight in asm, i.e., multiply 64*64 then divide by
>> 64 keeping the intermediate result on 128 bits?
> If you know of a way to do this for all 30 odd architectures supported
> by our beloved kernel, do let me know ;-)
:-)
> Yes I can do it for x86_64, but people tend to get mighty upset if you
> break the compile for all other arches...
rather than breaking compile, I was thinking more of using the
optimization for a more accurate comparison on archs that have 64-bit
mul and 128-bit cmp, and leaving the overflow on other archs. Though,
that would imply a difference in behavior on those borderline cases
(very big periods I guess).
However, I'm also puzzled from what would happen by compiling the
current code on mostly 16-bit micros which have very limited 32-bit
operations...
T.
--
Tommaso Cucinotta, Computer Engineering PhD, Researcher
ReTiS Lab, Scuola Superiore Sant'Anna, Pisa, Italy
Tel +39 050 882 024, Fax +39 050 882 003
http://retis.sssup.it/people/tommaso
next prev parent reply other threads:[~2012-04-23 23:21 UTC|newest]
Thread overview: 130+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-06 7:14 [RFC][PATCH 00/16] sched: SCHED_DEADLINE v4 Juri Lelli
2012-04-06 7:14 ` [PATCH 01/16] sched: add sched_class->task_dead Juri Lelli
2012-04-08 17:49 ` Oleg Nesterov
2012-04-08 18:09 ` Juri Lelli
2012-04-06 7:14 ` [PATCH 02/16] sched: add extended scheduling interface Juri Lelli
2012-04-06 7:14 ` [PATCH 03/16] sched: SCHED_DEADLINE data structures Juri Lelli
2012-04-23 9:08 ` Peter Zijlstra
2012-04-23 9:47 ` Juri Lelli
2012-04-23 9:49 ` Peter Zijlstra
2012-04-23 9:55 ` Juri Lelli
2012-04-23 10:12 ` Peter Zijlstra
2012-04-23 9:13 ` Peter Zijlstra
2012-04-23 9:28 ` Juri Lelli
2012-04-23 9:30 ` Peter Zijlstra
2012-04-23 9:36 ` Juri Lelli
2012-04-23 9:39 ` Peter Zijlstra
2012-04-23 9:34 ` Peter Zijlstra
2012-04-23 10:16 ` Juri Lelli
2012-04-23 10:28 ` Peter Zijlstra
2012-04-23 10:33 ` Juri Lelli
2012-04-06 7:14 ` [PATCH 04/16] sched: SCHED_DEADLINE SMP-related " Juri Lelli
2012-04-06 7:14 ` [PATCH 05/16] sched: SCHED_DEADLINE policy implementation Juri Lelli
2012-04-11 3:06 ` Steven Rostedt
2012-04-11 6:54 ` Juri Lelli
2012-04-11 13:41 ` Steven Rostedt
2012-04-11 13:55 ` Juri Lelli
2012-04-23 10:15 ` Peter Zijlstra
2012-04-23 10:18 ` Juri Lelli
2012-04-23 10:31 ` Peter Zijlstra
2012-04-23 10:37 ` Juri Lelli
2012-04-23 21:25 ` Tommaso Cucinotta
2012-04-23 21:45 ` Peter Zijlstra
2012-04-23 23:25 ` Tommaso Cucinotta
2012-04-24 6:29 ` Dario Faggioli
2012-04-24 6:52 ` Juri Lelli
2012-04-23 11:32 ` Peter Zijlstra
2012-04-23 12:13 ` Juri Lelli
2012-04-23 12:22 ` Peter Zijlstra
2012-04-23 13:37 ` Juri Lelli
2012-04-23 14:01 ` Peter Zijlstra
2012-04-23 11:34 ` Peter Zijlstra
2012-04-23 11:57 ` Juri Lelli
2012-04-23 11:55 ` Peter Zijlstra
2012-04-23 14:43 ` Juri Lelli
2012-04-23 15:11 ` Peter Zijlstra
2012-04-23 21:55 ` Tommaso Cucinotta
2012-04-23 21:58 ` Peter Zijlstra
2012-04-23 23:21 ` Tommaso Cucinotta [this message]
2012-04-24 9:50 ` Peter Zijlstra
2012-04-24 1:03 ` Steven Rostedt
2012-04-23 14:11 ` Peter Zijlstra
2012-04-23 14:25 ` Peter Zijlstra
2012-04-23 15:34 ` Juri Lelli
2012-04-23 14:35 ` Peter Zijlstra
2012-04-23 15:39 ` Juri Lelli
2012-04-23 15:43 ` Peter Zijlstra
2012-04-23 16:41 ` Juri Lelli
[not found] ` <4F95D41F.5060700@sssup.it>
2012-04-24 7:21 ` Juri Lelli
2012-04-24 9:00 ` Peter Zijlstra
2012-05-15 10:10 ` Juri Lelli
2012-04-23 15:15 ` Peter Zijlstra
2012-04-23 15:37 ` Juri Lelli
2012-04-06 7:14 ` [PATCH 06/16] sched: SCHED_DEADLINE push and pull logic Juri Lelli
2012-04-06 13:39 ` Hillf Danton
2012-04-06 17:31 ` Juri Lelli
2012-04-07 2:32 ` Hillf Danton
2012-04-07 7:46 ` Dario Faggioli
2012-04-08 20:20 ` Juri Lelli
2012-04-09 12:28 ` Hillf Danton
2012-04-10 8:11 ` Juri Lelli
2012-04-11 15:57 ` Steven Rostedt
2012-04-11 16:00 ` Steven Rostedt
2012-04-11 16:09 ` Juri Lelli
2012-04-11 14:10 ` Steven Rostedt
2012-04-12 12:28 ` Hillf Danton
2012-04-12 12:51 ` Steven Rostedt
2012-04-12 12:56 ` Hillf Danton
2012-04-12 13:35 ` Steven Rostedt
2012-04-12 13:41 ` Hillf Danton
2012-04-11 16:07 ` Steven Rostedt
2012-04-11 16:11 ` Juri Lelli
2012-04-11 16:14 ` Steven Rostedt
2012-04-19 13:44 ` Juri Lelli
2012-04-11 16:21 ` Steven Rostedt
2012-04-11 16:24 ` Juri Lelli
2012-04-11 16:33 ` Steven Rostedt
2012-04-24 13:15 ` Peter Zijlstra
2012-04-24 18:50 ` Steven Rostedt
2012-04-24 18:53 ` Peter Zijlstra
2012-04-24 19:01 ` Steven Rostedt
2012-04-11 17:25 ` Steven Rostedt
2012-04-11 17:48 ` Juri Lelli
2012-04-06 7:14 ` [PATCH 07/16] sched: SCHED_DEADLINE avg_update accounting Juri Lelli
2012-04-06 7:14 ` [PATCH 08/16] sched: add period support for -deadline tasks Juri Lelli
2012-04-11 20:32 ` Steven Rostedt
2012-04-11 21:56 ` Juri Lelli
2012-04-11 22:13 ` Tommaso Cucinotta
2012-04-12 0:19 ` Steven Rostedt
2012-04-12 6:39 ` Luca Abeni
2012-04-06 7:14 ` [PATCH 09/16] sched: add schedstats " Juri Lelli
2012-04-06 7:14 ` [PATCH 10/16] sched: add resource limits " Juri Lelli
2012-04-24 15:07 ` Peter Zijlstra
2012-04-24 15:22 ` Juri Lelli
2012-04-24 16:27 ` Peter Zijlstra
2012-04-24 17:14 ` Juri Lelli
2012-04-06 7:14 ` [PATCH 11/16] sched: add latency tracing " Juri Lelli
2012-04-11 21:03 ` Steven Rostedt
2012-04-12 7:16 ` Juri Lelli
2012-04-16 15:51 ` Daniel Vacek
2012-04-16 19:56 ` Steven Rostedt
2012-04-16 21:31 ` Daniel Vacek
2012-04-06 7:14 ` [PATCH 12/16] rtmutex: turn the plist into an rb-tree Juri Lelli
2012-04-11 21:11 ` Steven Rostedt
2012-04-22 14:28 ` Juri Lelli
2012-04-23 8:33 ` Peter Zijlstra
2012-04-23 11:37 ` Steven Rostedt
2012-04-06 7:14 ` [PATCH 13/16] sched: drafted deadline inheritance logic Juri Lelli
2012-04-12 2:42 ` Steven Rostedt
2012-04-22 14:04 ` Juri Lelli
2012-04-23 8:39 ` Peter Zijlstra
2012-04-06 7:14 ` [PATCH 14/16] sched: add bandwidth management for sched_dl Juri Lelli
2012-04-06 7:14 ` [PATCH 15/16] sched: speed up -dl pushes with a push-heap Juri Lelli
2012-04-06 7:14 ` [PATCH 16/16] sched: add sched_dl documentation Juri Lelli
2012-04-06 8:25 ` [RFC][PATCH 00/16] sched: SCHED_DEADLINE v4 Luca Abeni
2012-04-07 9:25 ` Tadeus Prastowo
2012-04-06 11:07 ` Dario Faggioli
2012-04-07 7:52 ` Juri Lelli
2012-04-11 14:17 ` [RFC][PATCH 00/16] sched: " Steven Rostedt
2012-04-11 14:28 ` Juri Lelli
-- strict thread matches above, loose matches on Subject: below --
2012-04-23 12:31 [PATCH 05/16] sched: SCHED_DEADLINE policy implementation cucinotta
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