From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Indan Zupancic <indan@nul.nu>,
Youquan Song <youquan.song@intel.com>,
Ingo Molnar <mingo@elte.hu>,
Arjan van de Ven <arjan@linux.intel.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>
Subject: Re: [RFC PATCH v1 1/2] sched: unified sched_powersavings sysfs tunable
Date: Wed, 25 Jan 2012 15:53:01 +0100 [thread overview]
Message-ID: <1327503181.2614.76.camel@laptop> (raw)
In-Reply-To: <20120116162241.29759.13220.stgit@localhost>
On Mon, 2012-01-16 at 21:52 +0530, Vaidyanathan Srinivasan wrote:
> +++ b/block/blk.h
> @@ -167,14 +167,15 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
> static inline int blk_cpu_to_group(int cpu)
> {
> int group = NR_CPUS;
> -#ifdef CONFIG_SCHED_MC
> - const struct cpumask *mask = cpu_coregroup_mask(cpu);
> - group = cpumask_first(mask);
> -#elif defined(CONFIG_SCHED_SMT)
> - group = cpumask_first(topology_thread_cpumask(cpu));
> +#ifdef CONFIG_SCHED_POWERSAVE
> + if (smt_capable())
> + group = cpumask_first(topology_thread_cpumask(cpu));
> + else
> + group = cpumask_first(cpu_coregroup_mask(cpu));
> #else
> return cpu;
> #endif
> + /* Possible dead code?? */
> if (likely(group < NR_CPUS))
> return group;
> return cpu;
After going, WTF is block doing! I had a closer look and this doesn't
seem right at all. The old code would use coregroup_mask when SCHED_MC
&& SCHED_SMT, the new code does something else.
Jens, what is this thing trying to do?
next prev parent reply other threads:[~2012-01-25 14:53 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 16:22 [RFC PATCH v1 0/2] sched: unified sched_powersavings tunables Vaidyanathan Srinivasan
2012-01-16 16:22 ` [RFC PATCH v1 1/2] sched: unified sched_powersavings sysfs tunable Vaidyanathan Srinivasan
2012-01-25 14:53 ` Peter Zijlstra [this message]
2012-01-26 10:42 ` Jens Axboe
2012-01-26 11:08 ` Peter Zijlstra
2012-01-26 11:26 ` Jens Axboe
2012-01-26 12:04 ` Peter Zijlstra
2012-01-26 12:13 ` Jens Axboe
2012-01-26 12:39 ` Peter Zijlstra
2012-01-26 12:46 ` Jens Axboe
2012-01-28 12:06 ` [tip:sched/core] sched, block: Unify cache detection tip-bot for Peter Zijlstra
2012-01-27 9:35 ` [RFC PATCH v1 1/2] sched: unified sched_powersavings sysfs tunable Vaidyanathan Srinivasan
2012-01-25 14:57 ` Peter Zijlstra
2012-01-27 9:16 ` Vaidyanathan Srinivasan
2012-01-25 15:10 ` Peter Zijlstra
2012-01-25 15:12 ` Arjan van de Ven
2012-01-25 15:36 ` Peter Zijlstra
2012-01-27 9:22 ` Vaidyanathan Srinivasan
2012-01-27 9:40 ` Peter Zijlstra
2012-01-16 16:22 ` [RFC PATCH v1 2/2] sched: fix group_capacity for thread level consolidation Vaidyanathan Srinivasan
2012-01-25 15:38 ` Peter Zijlstra
2012-01-27 9:10 ` Vaidyanathan Srinivasan
2012-01-17 18:44 ` [RFC PATCH v1 0/2] sched: unified sched_powersavings tunables Vaidyanathan Srinivasan
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