From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Juri Lelli <juri.lelli@gmail.com>,
mingo@redhat.com, rostedt@goodmis.org, 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, tommaso.cucinotta@sssup.it,
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,
jkacur@redhat.com, harald.gustafsson@ericsson.com,
vincent.guittot@linaro.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 01/16] math128: Introduce various 128bit primitives
Date: Fri, 26 Oct 2012 14:56:44 +0200 [thread overview]
Message-ID: <1351256204.16863.56.camel@twins> (raw)
In-Reply-To: <1351248244.16863.13.camel@twins>
On Fri, 2012-10-26 at 12:44 +0200, Peter Zijlstra wrote:
> > We can still have the user space interface handing in the information
> > in nsec resolution, but it's reasonable to scale it down to something
> > useful. Just shift the incoming information right by 10, so you're in
> > the 1us resolution for all the internal math and all your limitation
> > problems are gone. A shift by ten for converting back and forth to
> > nsecs is not a real performance issue.
>
> I'm fine with that.. all I wanted was to not have the undefined overflow
> we initially had.
Note that we still need the constraint checking with this, although with
both values shifted right 10 bits the range is now much bigger and
shouldn't be a practical limit anymore.
next prev parent reply other threads:[~2012-10-26 12:57 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-24 21:53 [RFC][PATCH 00/16] sched: SCHED_DEADLINE v6 Juri Lelli
2012-10-24 21:53 ` [PATCH 01/16] math128: Introduce various 128bit primitives Juri Lelli
2012-10-24 22:48 ` Juri Lelli
2012-10-24 23:18 ` Linus Torvalds
2012-10-25 0:08 ` Steven Rostedt
2012-10-25 0:09 ` Linus Torvalds
2012-10-25 13:47 ` Peter Zijlstra
2012-10-25 14:13 ` Peter Zijlstra
2012-10-25 22:26 ` Linus Torvalds
2012-10-26 8:49 ` Peter Zijlstra
2012-10-26 9:24 ` Ingo Molnar
2012-10-26 9:35 ` Peter Zijlstra
2012-10-26 9:42 ` Ingo Molnar
2012-10-26 9:54 ` Peter Zijlstra
2012-10-26 10:04 ` Ingo Molnar
2012-10-26 10:36 ` Thomas Gleixner
2012-10-26 10:44 ` Peter Zijlstra
2012-10-26 11:11 ` Ingo Molnar
2012-10-26 12:56 ` Peter Zijlstra [this message]
2012-10-26 18:12 ` Juri Lelli
2012-10-26 18:28 ` Steven Rostedt
2012-10-26 18:34 ` Thomas Gleixner
2012-10-26 18:41 ` Juri Lelli
2012-10-26 12:39 ` Steven Rostedt
2012-10-26 13:09 ` Steven Rostedt
2012-10-26 9:52 ` Harald Gustafsson
2012-10-26 15:17 ` Linus Torvalds
2012-10-25 5:21 ` Geert Uytterhoeven
2012-10-25 13:38 ` Peter Zijlstra
2012-10-24 21:53 ` [PATCH 02/16] math128, x86_64: Implement {mul,add}_u128 in 64bit asm Juri Lelli
2012-10-24 22:27 ` H. Peter Anvin
2012-10-24 22:47 ` Juri Lelli
2012-10-24 22:51 ` H. Peter Anvin
2012-10-24 21:53 ` [PATCH 03/16] sched: add sched_class->task_dead Juri Lelli
2012-10-24 21:53 ` [PATCH 04/16] sched: add extended scheduling interface Juri Lelli
2012-10-24 21:53 ` [PATCH 05/16] sched: SCHED_DEADLINE structures & implementation Juri Lelli
2012-10-24 21:53 ` [PATCH 06/16] sched: SCHED_DEADLINE SMP-related data structures & logic Juri Lelli
2012-10-24 21:53 ` [PATCH 07/16] sched: SCHED_DEADLINE avg_update accounting Juri Lelli
2012-10-24 21:53 ` [PATCH 08/16] sched: add period support for -deadline tasks Juri Lelli
2012-10-24 21:53 ` [PATCH 09/16] sched: add schedstats " Juri Lelli
2012-10-24 21:53 ` [PATCH 10/16] sched: add latency tracing " Juri Lelli
2012-10-24 21:53 ` [PATCH 11/16] rtmutex: turn the plist into an rb-tree Juri Lelli
2012-10-24 21:53 ` [PATCH 12/16] sched: drafted deadline inheritance logic Juri Lelli
2012-10-24 21:53 ` [PATCH 13/16] sched: add bandwidth management for sched_dl Juri Lelli
2012-10-24 21:53 ` [PATCH 14/16] sched: make dl_bw a sub-quota of rt_bw Juri Lelli
2012-10-24 21:53 ` [PATCH 15/16] sched: speed up -dl pushes with a push-heap Juri Lelli
2012-10-24 21:53 ` [PATCH 16/16] sched: add sched_dl documentation Juri Lelli
2012-10-25 7:18 ` [RFC][PATCH 00/16] sched: SCHED_DEADLINE v6 Ingo Molnar
2012-10-25 9:53 ` Borislav Petkov
2012-10-25 16:58 ` Juri Lelli
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