From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Youquan Song <youquan.song@intel.com>
Cc: 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: Mon, 09 Jan 2012 12:05:56 +0100 [thread overview]
Message-ID: <1326107156.2442.59.camel@twins> (raw)
In-Reply-To: <20120110001445.GA20542@linux-youquan.bj.intel.com>
On Mon, 2012-01-09 at 19:14 -0500, Youquan Song wrote:
> Fine, I will base your suggestion to develop another patch soon.
>
>
> @@ -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)
> + sgs->group_capacity *= 2;
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.
next prev parent reply other threads:[~2012-01-09 11:06 UTC|newest]
Thread overview: 37+ 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 [this message]
2012-01-10 5:58 ` Youquan Song
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 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 14:46 ` 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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