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From: Youquan Song <youquan.song@intel.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Youquan Song <youquan.song@intel.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de,
	hpa@zytor.com, akpm@linux-foundation.org, stable@vger.kernel.org,
	suresh.b.siddha@intel.com, arjan@linux.intel.com,
	len.brown@intel.com, anhua.xu@intel.com, chaohong.guo@intel.com,
	Youquan Song <youquan.song@linux.intel.com>
Subject: Re: [PATCH] x86,sched: Fix sched_smt_power_savings totally broken
Date: Tue, 10 Jan 2012 00:58:56 -0500	[thread overview]
Message-ID: <20120110055856.GA23741@linux-youquan.bj.intel.com> (raw)
In-Reply-To: <1326107156.2442.59.camel@twins>

> Note, this has the hard-coded assumption you only have 2 threads per
> core, which while true for intel, isn't true in general. I think you
> meant to write *= group->group_weight or somesuch.
> 
> Also, you forgot to limit this to the SD_SHARE_CPUPOWER domain, you're
> now doubling the capacity for all domains.
> 
> Furthermore, have a look at the SD_PREFER_SIBLING logic and make sure
> you're not fighting that.
> 
Thanks Peter! Here is the patch. 

-Youquan

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a4d2b7a..4ada3e7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3923,6 +3923,10 @@ static inline void update_sg_lb_stats(struct
sched_domain *sd,
                                                SCHED_POWER_SCALE);
        if (!sgs->group_capacity)
                sgs->group_capacity = fix_small_capacity(sd, group);
+
+       if (sched_smt_power_savings && !(sd->flags & SD_SHARE_CPUPOWER))
+               sgs->group_capacity = group->group_weight;
+
        sgs->group_weight = group->group_weight;

        if (sgs->group_capacity > sgs->sum_nr_running)

  reply	other threads:[~2012-01-09 16:41 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-09  8:56 [PATCH] x86,sched: Fix sched_smt_power_savings totally broken Youquan Song
2012-01-09 10:06 ` Peter Zijlstra
2012-01-09 10:28   ` Peter Zijlstra
2012-01-09 10:30     ` Peter Zijlstra
2012-01-09 11:00     ` Vaidyanathan Srinivasan
2012-01-09 14:35       ` Peter Zijlstra
2012-01-09 16:03         ` Vaidyanathan Srinivasan
2012-01-09 16:13           ` Peter Zijlstra
2012-01-09 17:05             ` Vaidyanathan Srinivasan
2012-01-09 14:13     ` Arjan van de Ven
2012-05-18 10:19     ` [tip:sched/core] sched: Remove stale power aware scheduling remnants and dysfunctional knobs tip-bot for Peter Zijlstra
2012-01-10  0:14   ` [PATCH] x86,sched: Fix sched_smt_power_savings totally broken Youquan Song
2012-01-09 11:05     ` Peter Zijlstra
2012-01-10  5:58       ` Youquan Song [this message]
2012-01-09 23:52         ` Suresh Siddha
2012-01-10  9:18           ` Ingo Molnar
2012-01-10 14:32             ` Arjan van de Ven
2012-01-10 14:41               ` Peter Zijlstra
2012-01-10 14:54                 ` Arjan van de Ven
2012-01-10 15:32               ` Vincent Guittot
2012-01-10 15:32                 ` Vincent Guittot
2012-01-10 16:49               ` Vaidyanathan Srinivasan
2012-01-10 19:41               ` Ingo Molnar
2012-01-10 19:44                 ` Ingo Molnar
2012-01-10 16:54           ` Youquan Song
2012-01-10 16:51             ` Vaidyanathan Srinivasan
2012-01-10 19:01               ` Suresh Siddha
2012-01-11  3:52                 ` Vaidyanathan Srinivasan
2012-01-11 17:37                   ` Youquan Song
2012-01-10 16:44       ` Vaidyanathan Srinivasan
2012-01-09 11:12     ` Peter Zijlstra
2012-01-09 14:29       ` Vincent Guittot
2012-01-09 14:29         ` Vincent Guittot
2012-01-09 14:46         ` Peter Zijlstra
2012-01-10  2:12           ` Indan Zupancic
2012-01-10  9:26             ` Peter Zijlstra
2012-01-10  1:54         ` Suresh Siddha
2012-01-10  8:08           ` Vincent Guittot
2012-01-09 15:37 ` Greg KH

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