From: Alex Shi <alex.shi@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org, mingo@redhat.com,
tglx@linutronix.de, akpm@linux-foundation.org,
arjan@linux.intel.com, bp@alien8.de, pjt@google.com,
namhyung@kernel.org, efault@gmx.de, vincent.guittot@linaro.org,
gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com,
viresh.kumar@linaro.org, linux-kernel@vger.kernel.org
Subject: Re: [patch v4 03/18] sched: fix find_idlest_group mess logical
Date: Wed, 13 Feb 2013 23:07:44 +0800 [thread overview]
Message-ID: <511BAC40.6080009@intel.com> (raw)
In-Reply-To: <1360664208.4485.8.camel@laptop>
On 02/12/2013 06:16 PM, Peter Zijlstra wrote:
> On Thu, 2013-01-24 at 11:06 +0800, Alex Shi wrote:
>> There is 4 situations in the function:
>> 1, no task allowed group;
>> so min_load = ULONG_MAX, this_load = 0, idlest = NULL
>> 2, only local group task allowed;
>> so min_load = ULONG_MAX, this_load assigned, idlest = NULL
>> 3, only non-local task group allowed;
>> so min_load assigned, this_load = 0, idlest != NULL
>> 4, local group + another group are task allowed.
>> so min_load assigned, this_load assigned, idlest != NULL
>>
>> Current logical will return NULL in first 3 kinds of scenarios.
>> And still return NULL, if idlest group is heavier then the
>> local group in the 4th situation.
>>
>> Actually, I thought groups in situation 2,3 are also eligible to host
>> the task. And in 4th situation, agree to bias toward local group.
>
> I'm not convinced this is actually a cleanup.. taken together with patch
> 4 (which is a direct consequence of this patch afaict) you replace one
> conditional with 2.
>
The current logical will always miss the eligible CPU in the 3rd
situation. 'sd = sd->child' still skip the non-local group eligible CPU.
--
Thanks
Alex
next prev parent reply other threads:[~2013-02-13 15:08 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-24 3:06 [patch v4 0/18] sched: simplified fork, release load avg and power awareness scheduling Alex Shi
2013-01-24 3:06 ` [patch v4 01/18] sched: set SD_PREFER_SIBLING on MC domain to reduce a domain level Alex Shi
2013-02-12 10:11 ` Peter Zijlstra
2013-02-13 13:22 ` Alex Shi
2013-02-15 12:38 ` Peter Zijlstra
2013-02-16 5:16 ` Alex Shi
2013-02-13 14:17 ` Alex Shi
2013-01-24 3:06 ` [patch v4 02/18] sched: select_task_rq_fair clean up Alex Shi
2013-02-12 10:14 ` Peter Zijlstra
2013-02-13 14:44 ` Alex Shi
2013-01-24 3:06 ` [patch v4 03/18] sched: fix find_idlest_group mess logical Alex Shi
2013-02-12 10:16 ` Peter Zijlstra
2013-02-13 15:07 ` Alex Shi [this message]
2013-01-24 3:06 ` [patch v4 04/18] sched: don't need go to smaller sched domain Alex Shi
2013-01-24 3:06 ` [patch v4 05/18] sched: quicker balancing on fork/exec/wake Alex Shi
2013-02-12 10:22 ` Peter Zijlstra
2013-02-14 3:13 ` Alex Shi
2013-02-14 8:12 ` Preeti U Murthy
2013-02-14 14:08 ` Alex Shi
2013-02-15 13:00 ` Peter Zijlstra
2013-01-24 3:06 ` [patch v4 06/18] sched: give initial value for runnable avg of sched entities Alex Shi
2013-02-12 10:23 ` Peter Zijlstra
2013-01-24 3:06 ` [patch v4 07/18] sched: set initial load avg of new forked task Alex Shi
2013-02-12 10:26 ` Peter Zijlstra
2013-02-13 15:14 ` Alex Shi
2013-02-13 15:41 ` Paul Turner
2013-02-14 13:07 ` Alex Shi
2013-02-19 11:34 ` Paul Turner
2013-02-20 4:18 ` Preeti U Murthy
2013-02-20 5:13 ` Alex Shi
2013-01-24 3:06 ` [patch v4 08/18] Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking" Alex Shi
2013-02-12 10:27 ` Peter Zijlstra
2013-02-13 15:23 ` Alex Shi
2013-02-13 15:45 ` Paul Turner
2013-02-14 3:07 ` Preeti U Murthy
2013-01-24 3:06 ` [patch v4 09/18] sched: add sched_policies in kernel Alex Shi
2013-02-12 10:36 ` Peter Zijlstra
2013-02-13 15:41 ` Alex Shi
2013-01-24 3:06 ` [patch v4 10/18] sched: add sysfs interface for sched_policy selection Alex Shi
2013-01-24 3:06 ` [patch v4 11/18] sched: log the cpu utilization at rq Alex Shi
2013-02-12 10:39 ` Peter Zijlstra
2013-02-14 3:10 ` Alex Shi
2013-01-24 3:06 ` [patch v4 12/18] sched: add power aware scheduling in fork/exec/wake Alex Shi
2013-01-24 3:06 ` [patch v4 13/18] sched: packing small tasks in wake/exec balancing Alex Shi
2013-01-24 3:06 ` [patch v4 14/18] sched: add power/performance balance allowed flag Alex Shi
2013-01-24 3:06 ` [patch v4 15/18] sched: pull all tasks from source group Alex Shi
2013-01-24 3:06 ` [patch v4 16/18] sched: don't care if the local group has capacity Alex Shi
2013-01-24 3:06 ` [patch v4 17/18] sched: power aware load balance, Alex Shi
2013-01-24 3:07 ` [patch v4 18/18] sched: lazy power balance Alex Shi
2013-01-24 9:44 ` [patch v4 0/18] sched: simplified fork, release load avg and power awareness scheduling Borislav Petkov
2013-01-24 15:07 ` Alex Shi
2013-01-27 2:41 ` Alex Shi
2013-01-27 4:36 ` Mike Galbraith
2013-01-27 10:35 ` Borislav Petkov
2013-01-27 13:25 ` Alex Shi
2013-01-27 15:51 ` Mike Galbraith
2013-01-28 5:17 ` Mike Galbraith
2013-01-28 5:51 ` Alex Shi
2013-01-28 6:15 ` Mike Galbraith
2013-01-28 6:42 ` Mike Galbraith
2013-01-28 7:20 ` Mike Galbraith
2013-01-29 1:17 ` Alex Shi
2013-01-28 9:55 ` Borislav Petkov
2013-01-28 10:44 ` Mike Galbraith
2013-01-28 11:29 ` Borislav Petkov
2013-01-28 11:32 ` Mike Galbraith
2013-01-28 11:40 ` Mike Galbraith
2013-01-28 15:22 ` Borislav Petkov
2013-01-28 15:55 ` Mike Galbraith
2013-01-29 1:38 ` Alex Shi
2013-01-29 1:32 ` Alex Shi
2013-01-29 1:36 ` Alex Shi
2013-01-28 15:47 ` Mike Galbraith
2013-01-29 1:45 ` Alex Shi
2013-01-29 4:03 ` Mike Galbraith
2013-01-29 2:27 ` Alex Shi
2013-01-27 10:40 ` Borislav Petkov
2013-01-27 14:03 ` Alex Shi
2013-01-28 5:19 ` Alex Shi
2013-01-28 6:49 ` Mike Galbraith
2013-01-28 7:17 ` Alex Shi
2013-01-28 7:33 ` Mike Galbraith
2013-01-29 6:02 ` Alex Shi
2013-01-28 1:28 ` Alex Shi
2013-02-04 1:35 ` Alex Shi
2013-02-04 11:09 ` Ingo Molnar
2013-02-05 2:26 ` Alex Shi
2013-02-06 5:08 ` Alex Shi
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