Re: [PATCH 1/3] sched/fair: Prepare variables for increased precision of EAS estimated energy
From: Lukasz Luba <lukasz.luba@arm.com>
Date: 2021-07-07 11:02:30
Also in:
lkml
From: Lukasz Luba <lukasz.luba@arm.com>
Date: 2021-07-07 11:02:30
Also in:
lkml
On 7/7/21 11:50 AM, Vincent Guittot wrote:
On Wed, 7 Jul 2021 at 12:41, Lukasz Luba [off-list ref] wrote:quoted
On 7/7/21 11:32 AM, Vincent Guittot wrote:quoted
On Wed, 7 Jul 2021 at 12:29, Lukasz Luba [off-list ref] wrote:quoted
On 7/7/21 11:11 AM, Vincent Guittot wrote:quoted
On Wed, 7 Jul 2021 at 12:06, Lukasz Luba [off-list ref] wrote:quoted
[snip]quoted
quoted
No. It's in 0.1uW scale, so 800Watts. Which is 16 CPUs * 64WattsOh! you want 0.1uW precision .... This doesn't seem realistic at all. I'm not even sure that the power model can even reach an accuracy of 1mWTrue, the EM is registering platform with 1mW precision, but 1uWDo you mean 1uW or 0.1uW ?In this patch set I've proposed 0.1uW, but I'm open to drop one order of magnitude. The 1uW still be good.I don't want to underestimate the capabilities of the power model but I don't see which benefit you will get with 0.1uW precision With a 1uW precision the long type currently used for the returned value is fine for 32bits machine AFAICT
For 1uW and 1.2Watts for one core, 4 CPUs in cluster we get: (1200 * 1000) * (4 * 1024) = ~4.9bln so it would need div 64 version