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From: Ingo Molnar <mingo@elte.hu>
To: Nikhil Rao <ncrao@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Mike Galbraith <efault@gmx.de>,
	linux-kernel@vger.kernel.org,
	"Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de>
Subject: Re: [PATCH v1 00/19] Increase resolution of load weights
Date: Wed, 4 May 2011 13:13:55 +0200	[thread overview]
Message-ID: <20110504111355.GC5914@elte.hu> (raw)
In-Reply-To: <BANLkTiktch2mHDLXZCdCED3XoqmkVRfghA@mail.gmail.com>


* Nikhil Rao <ncrao@google.com> wrote:

> Also, out of curiosity, what's an acceptable tolerance level for a 
> performance hit on 32-bit?

It's a cost/benefit analysis and for 32-bit systems the benefits seem to be 
rather small, right?

Can we make the increase in resolution dependent on max CPU count or such and 
use cheaper divides on 32-bit in that case, while still keeping the code clean? 

We'd expect only relatively large and new (and 64-bit) systems to run into 
resolution problems, right?

Thanks,

	Ingo

  parent reply	other threads:[~2011-05-04 11:14 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-02  1:18 [PATCH v1 00/19] Increase resolution of load weights Nikhil Rao
2011-05-02  1:18 ` [PATCH v1 01/19] sched: introduce SCHED_POWER_SCALE to scale cpu_power calculations Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 02/19] sched: increase SCHED_LOAD_SCALE resolution Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 03/19] sched: use u64 for load_weight fields Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 04/19] sched: update cpu_load to be u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 05/19] sched: update this_cpu_load() to return u64 value Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 06/19] sched: update source_load(), target_load() and weighted_cpuload() to use u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 07/19] sched: update find_idlest_cpu() to use u64 for load Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 08/19] sched: update find_idlest_group() to use u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 09/19] sched: update division in cpu_avg_load_per_task to use div_u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 10/19] sched: update wake_affine path to use u64, s64 for weights Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 11/19] sched: update update_sg_lb_stats() to use u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 12/19] sched: Update update_sd_lb_stats() " Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 13/19] sched: update f_b_g() to use u64 for weights Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 14/19] sched: change type of imbalance to be u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 15/19] sched: update h_load to use u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 16/19] sched: update move_task() and helper functions to use u64 for weights Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 17/19] sched: update f_b_q() to use u64 for weighted cpuload Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 18/19] sched: update shares distribution to use u64 Nikhil Rao
2011-05-02  1:19 ` [PATCH v1 19/19] sched: convert atomic ops in shares update to use atomic64_t ops Nikhil Rao
2011-05-02  6:14 ` [PATCH v1 00/19] Increase resolution of load weights Ingo Molnar
2011-05-04  0:58   ` Nikhil Rao
2011-05-04  1:07     ` Nikhil Rao
2011-05-04 11:13     ` Ingo Molnar [this message]
2011-05-06  1:29       ` Nikhil Rao
2011-05-06  6:59         ` Ingo Molnar
2011-05-11  0:14           ` Nikhil Rao
2011-05-11  6:59             ` Ingo Molnar
2011-05-12  8:56               ` Nikhil Rao
2011-05-12 10:55                 ` Ingo Molnar
2011-05-12 18:44                   ` Nikhil Rao
2011-05-12  9:08         ` Peter Zijlstra
2011-05-12 17:30           ` Nikhil Rao
2011-05-13  7:19             ` Peter Zijlstra

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