linux-kernel - Re: [patch v8 3/9] sched: set initial value of runnable avg for new forked task

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <51BE5958.6020602@intel.com>
Date:	Mon, 17 Jun 2013 08:33:28 +0800
From:	Alex Shi <alex.shi@...el.com>
To:	Lei Wen <adrian.wenl@...il.com>
CC:	mingo@...hat.com, peterz@...radead.org, tglx@...utronix.de,
	akpm@...ux-foundation.org, bp@...en8.de, pjt@...gle.com,
	namhyung@...nel.org, efault@....de, morten.rasmussen@....com,
	vincent.guittot@...aro.org, preeti@...ux.vnet.ibm.com,
	viresh.kumar@...aro.org, linux-kernel@...r.kernel.org,
	mgorman@...e.de, riel@...hat.com, wangyun@...ux.vnet.ibm.com,
	Jason Low <jason.low2@...com>,
	Changlong Xie <changlongx.xie@...el.com>, sgruszka@...hat.com,
	fweisbec@...il.com
Subject: Re: [patch v8 3/9] sched: set initial value of runnable avg for new
 forked task

On 06/15/2013 08:09 PM, Lei Wen wrote:
>>>>> >>> > and make forking balancing imbalance since incorrect load_avg_contrib.
>>>>> >>> >
>>>>> >>> > Further more, Morten Rasmussen notice some tasks were not launched at
>>>>> >>> > once after created. So Paul and Peter suggest giving a start value for
>>>>> >>> > new task runnable avg time same as sched_slice().
>>> >> I am confused at this comment, how set slice to runnable avg would change
>>> >> the behavior of "some tasks were not launched at once after created"?
>> >
>> > I also don't know the details on Morten's machine. but just guess, there
>> > are much tasks on in the run queue. the minimum load avg make the new
>> > task wait its time...
> Is there some possibility that since task structure is allocated without being
> set to 0, and it cause the imbalance between runqueues. Then the new forked
> is migrated to other cpus, so that it cause its execution being delayed?

Is there sth weird happens?
The task should be running a while before migration. and periodic load
balance also need some time to happen. So generally, it has no such worries.

-- 
Thanks
    Alex
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/