From: Michael Wang <wangyun@linux.vnet.ibm.com>
To: Alex Shi <alex.shi@intel.com>
Cc: mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de,
akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de,
pjt@google.com, namhyung@kernel.org, efault@gmx.de,
morten.rasmussen@arm.com, vincent.guittot@linaro.org,
gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com,
viresh.kumar@linaro.org, linux-kernel@vger.kernel.org,
len.brown@intel.com, rafael.j.wysocki@intel.com, jkosina@suse.cz,
clark.williams@gmail.com, tony.luck@intel.com,
keescook@chromium.org, mgorman@suse.de, riel@redhat.com
Subject: Re: [patch v3 0/8] sched: use runnable avg in load balance
Date: Wed, 03 Apr 2013 13:38:20 +0800 [thread overview]
Message-ID: <515BC04C.6050403@linux.vnet.ibm.com> (raw)
In-Reply-To: <515BAFE6.1020804@intel.com>
On 04/03/2013 12:28 PM, Alex Shi wrote:
[snip]
>
> but the patch may cause some unfairness if this/prev cpu are not burst at
> same time. So could like try the following patch?
I will try it later, some doubt below :)
[snip]
> +
> + if (cpu_rq(this_cpu)->avg_idle < sysctl_sched_migration_cost ||
> + cpu_rq(prev_cpu)->avg_idle < sysctl_sched_migration_cost)
> + burst= 1;
> +
> + /* use instant load for bursty waking up */
> + if (!burst) {
> + load = source_load(prev_cpu, idx);
> + this_load = target_load(this_cpu, idx);
> + } else {
> + load = cpu_rq(prev_cpu)->load.weight;
> + this_load = cpu_rq(this_cpu)->load.weight;
Ok, my understanding is, we want pull if 'prev_cpu' is burst, and don't
want pull if 'this_cpu' is burst, correct?
And we do this by guess the load higher or lower, is that right?
And I think target_load() is capable enough to choose the higher load,
if 'cpu_rq(cpu)->load.weight' is really higher, the results will be the
same.
So what about this:
/* prefer higher load if burst */
load = burst_prev ?
target_load(prev_cpu, idx) : source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
Regards,
Michael Wang
> + }
>
> /*
> * If sync wakeup then subtract the (maximum possible)
>
next prev parent reply other threads:[~2013-04-03 5:38 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-02 3:23 [patch v3 0/8] sched: use runnable avg in load balance Alex Shi
2013-04-02 3:23 ` [patch v3 1/8] Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking" Alex Shi
2013-04-02 3:23 ` [patch v3 2/8] sched: set initial value of runnable avg for new forked task Alex Shi
2013-04-02 3:23 ` [patch v3 3/8] sched: only count runnable avg on cfs_rq's nr_running Alex Shi
2013-04-03 3:19 ` Alex Shi
2013-04-02 3:23 ` [patch v3 4/8] sched: update cpu load after task_tick Alex Shi
2013-04-02 3:23 ` [patch v3 5/8] sched: compute runnable load avg in cpu_load and cpu_avg_load_per_task Alex Shi
2013-04-02 3:23 ` [patch v3 6/8] sched: consider runnable load average in move_tasks Alex Shi
2013-04-09 7:08 ` Vincent Guittot
2013-04-09 8:05 ` Alex Shi
2013-04-09 8:58 ` Vincent Guittot
2013-04-09 10:38 ` Alex Shi
2013-04-09 11:56 ` Vincent Guittot
2013-04-09 14:48 ` Alex Shi
2013-04-09 15:16 ` Vincent Guittot
2013-04-10 2:31 ` Alex Shi
2013-04-10 6:07 ` Michael Wang
2013-04-10 6:55 ` Vincent Guittot
2013-04-02 3:23 ` [patch v3 7/8] sched: consider runnable load average in effective_load Alex Shi
2013-04-02 3:23 ` [patch v3 8/8] sched: use instant load for burst wake up Alex Shi
2013-04-02 7:23 ` [patch v3 0/8] sched: use runnable avg in load balance Michael Wang
2013-04-02 8:34 ` Mike Galbraith
2013-04-02 9:13 ` Michael Wang
2013-04-02 8:35 ` Alex Shi
2013-04-02 9:45 ` Michael Wang
2013-04-03 2:46 ` Michael Wang
2013-04-03 2:56 ` Alex Shi
2013-04-03 3:23 ` Michael Wang
2013-04-03 4:28 ` Alex Shi
2013-04-03 5:38 ` Michael Wang [this message]
2013-04-03 5:53 ` Michael Wang
2013-04-03 6:01 ` Alex Shi
2013-04-03 6:22 ` Michael Wang
2013-04-03 6:53 ` Alex Shi
2013-04-03 7:18 ` Michael Wang
2013-04-03 7:28 ` Alex Shi
2013-04-03 8:46 ` Alex Shi
2013-04-03 9:37 ` Michael Wang
2013-04-03 11:17 ` Alex Shi
2013-04-07 3:09 ` Michael Wang
2013-04-07 7:30 ` Alex Shi
2013-04-07 8:56 ` Michael Wang
2013-04-09 5:08 ` Alex Shi
2013-04-10 13:12 ` Alex Shi
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