From: Peter Zijlstra <peterz@infradead.org>
To: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>,
lenb@kernel.org, rjw@rjwysocki.net,
Chris Leech <christopher.leech@intel.com>,
David Miller <davem@davemloft.net>,
rui.zhang@intel.com, jacob.jun.pan@linux.intel.com,
Mike Galbraith <bitbucket@online.de>,
Ingo Molnar <mingo@kernel.org>,
hpa@zytor.com, Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH 6/7] sched: Clean up preempt_enable_no_resched() abuse
Date: Fri, 22 Nov 2013 12:30:44 +0100 [thread overview]
Message-ID: <20131122113044.GL10022@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <528F0000.7000505@linux.intel.com>
On Fri, Nov 22, 2013 at 08:56:00AM +0200, Eliezer Tamir wrote:
> On 21/11/2013 15:39, Peter Zijlstra wrote:
> > On Thu, Nov 21, 2013 at 03:26:17PM +0200, Eliezer Tamir wrote:
>
> >> We don't override any limit the user has put on the system call.
> >
> > You are in fact, note how the normal select @endtime argument is only
> > set up _after_ you're done polling. So if the syscall had a timeout of 5
> > seconds, you just blew it by 55.
> >
>
> That's a bug, we will fix it.
The entire thing is a bug, and if I could take away sched_clock() from
you I would, but sadly its all inlines so I can't :-(
Please use local_clock(), yes its slightly more expensive, but I doubt
you can actually measure the effects on sane hardware.
next prev parent reply other threads:[~2013-11-22 11:30 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-20 16:04 [PATCH 0/7] Cure some vaux idle wrackage Peter Zijlstra
2013-11-20 16:04 ` [PATCH 1/7] x86, acpi, idle: Restructure the mwait idle routines Peter Zijlstra
2013-11-20 16:04 ` [PATCH 2/7] sched, preempt: Fixup missed PREEMPT_NEED_RESCHED folding Peter Zijlstra
2013-11-21 8:25 ` Peter Zijlstra
2013-11-20 16:04 ` [PATCH 3/7] idle, thermal, acpi: Remove home grown idle implementations Peter Zijlstra
2013-11-20 16:40 ` Arjan van de Ven
2013-11-20 16:59 ` Peter Zijlstra
2013-11-20 17:23 ` Thomas Gleixner
2013-11-20 17:23 ` Arjan van de Ven
2013-11-20 17:55 ` Thomas Gleixner
2013-11-20 18:21 ` Arjan van de Ven
2013-11-20 19:38 ` Thomas Gleixner
2013-11-20 22:08 ` Jacob Pan
2013-11-21 0:54 ` Jacob Pan
2013-11-21 8:21 ` Peter Zijlstra
2013-11-21 16:07 ` Paul E. McKenney
2013-11-21 16:21 ` Arjan van de Ven
2013-11-21 19:19 ` Paul E. McKenney
2013-11-21 19:45 ` Arjan van de Ven
2013-11-21 20:07 ` Paul E. McKenney
2013-11-22 0:10 ` Jacob Pan
2013-11-22 4:20 ` Paul E. McKenney
2013-11-22 11:33 ` Peter Zijlstra
2013-11-22 17:17 ` Paul E. McKenney
2013-11-21 16:29 ` Peter Zijlstra
2013-11-21 17:27 ` Paul E. McKenney
2013-11-20 16:04 ` [PATCH 4/7] preempt, locking: Rework local_bh_{dis,en}able() Peter Zijlstra
2013-11-20 16:04 ` [PATCH 5/7] locking: Optimize lock_bh functions Peter Zijlstra
2013-11-20 16:04 ` [PATCH 6/7] sched: Clean up preempt_enable_no_resched() abuse Peter Zijlstra
2013-11-20 18:02 ` Eliezer Tamir
2013-11-20 18:15 ` Peter Zijlstra
2013-11-20 20:14 ` Eliezer Tamir
2013-11-21 10:10 ` Peter Zijlstra
2013-11-21 13:26 ` Eliezer Tamir
2013-11-21 13:39 ` Peter Zijlstra
2013-11-22 6:56 ` Eliezer Tamir
2013-11-22 11:30 ` Peter Zijlstra [this message]
2013-11-26 7:15 ` Eliezer Tamir
2013-11-26 10:51 ` Thomas Gleixner
2013-11-20 16:04 ` [PATCH 7/7] preempt: Take away preempt_enable_no_resched() from modules Peter Zijlstra
2013-11-20 18:54 ` Jacob Pan
2013-11-20 19:00 ` Peter Zijlstra
2013-11-20 19:18 ` Peter Zijlstra
2013-11-20 19:29 ` Jacob Pan
2013-11-20 16:34 ` [PATCH 0/7] Cure some vaux idle wrackage Peter Zijlstra
2013-11-20 17:19 ` Jacob Pan
2013-11-20 17:24 ` Peter Zijlstra
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