linux-kernel - RE: [RFT][PATCH v1] cpuidle: teo: Avoid selecting deepest idle state over-eagerly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <000e01db7bce$e1d3b8b0$a57b2a10$@telus.net>
Date: Mon, 10 Feb 2025 07:17:21 -0800
From: "Doug Smythies" <dsmythies@...us.net>
To: "'Rafael J. Wysocki'" <rafael@...nel.org>
Cc: "'Rafael J. Wysocki'" <rjw@...ysocki.net>,
	"'LKML'" <linux-kernel@...r.kernel.org>,
	"'Daniel Lezcano'" <daniel.lezcano@...aro.org>,
	"'Christian Loehle'" <christian.loehle@....com>,
	"'Artem Bityutskiy'" <artem.bityutskiy@...ux.intel.com>,
	"'Aboorva Devarajan'" <aboorvad@...ux.ibm.com>,
	"'Linux PM'" <linux-pm@...r.kernel.org>,
	"Doug Smythies" <dsmythies@...us.net>
Subject: RE: [RFT][PATCH v1] cpuidle: teo: Avoid selecting deepest idle state over-eagerly

On 2025.02.08 03:25 Rafael J. Wysocki wrote:
>On Sat, Feb 8, 2025 at 12:40 AM Doug Smythies <dsmythies@...us.net> wrote:
>> On 2025.02.04 12:58 Rafael J. Wysocki wrote:
>>>
>>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

... snip ...
>>
>> Test durations were >= 45 minutes each.
>>
>> Kernel 6.14-rc1: Includes cpuidle: teo: Cleanups and very frequent wakeups handling update
>> Average Idle Power: teo governor: 2.199 watts (+25.51%)
>> Average Idle power: menu governor: 1.873 watts (+6.91%)
>
> menu hasn't changed in 6.14-rc1, so this would be variation between
>runs I suppose.

Perhaps the way I presented my data wasn't the best method.
All the % were relative to kernel 6.13 and the teo idle governor.
Relative to kernel 6.13 menu governor that would be: -1.9%,
certainly within the noise floor.
 
>> Kernel 6.14-rc1-p: Added this patch for teo and "cpuidle: menu: Avoid discarding useful information when processing recent idle intervals" for menu
>> Average Idle Power: teo governor: 9.401 watts (+436.6%)
>> Only 69.61% idle is in the deepest idle state. More typically it would be 98% to 99%.
>
> Ah, not good.
>
> OK, this clearly doesn't go in the right direction.
>
>> 28.6531% idle time is in state 1. More typically it would be 0.03%
>> Average Idle Power: menu governor: 1.820 watts (+3.9%)
>>
>> Kernel 6.13: before "cpuidle: teo: Cleanups and very frequent wakeups handling update"
>> Average Idle Power: teo governor: 1.752 watts (reference: 0.0%)
>> Average Idle power: menu governor: 1.909 watts (+9.0%)
>
> Thanks, I'm just going to drop this patch then.
>
> If you don't mind, I'll have a couple more teo updates for testing.

O.K. I'll watch for the patches.
Plenty to do in the meantime, acquiring baseline data and continuing with the:
"cpuidle: menu: Avoid discarding useful information when processing recent idle intervals"
patch set portion of kernel 6.14-rc1-p