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From:   Anna-Maria Behnsen <anna-maria@linutronix.de>
To:     "Pandruvada, Srinivas" <srinivas.pandruvada@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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Subject: Re: [PATCH v8 00/25] timer: Move from a push remote at enqueue to a
 pull at expiry model
In-Reply-To: <151240c939d02df4979651b84bb99356a938c44d.camel@intel.com>
References: <20231004123454.15691-1-anna-maria@linutronix.de>
 <151240c939d02df4979651b84bb99356a938c44d.camel@intel.com>
Date:   Thu, 19 Oct 2023 15:47:26 +0200
Message-ID: <87pm1a911t.fsf@somnus>
MIME-Version: 1.0
Content-Type: text/plain
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"Pandruvada, Srinivas" <srinivas.pandruvada@intel.com> writes:

> Hi Maria,
>
> On Wed, 2023-10-04 at 14:34 +0200, Anna-Maria Behnsen wrote:
>> Hi,
>> 
>> 
>
> [...]
>
>> 
>> The proper solution to this problem is to always queue the timers on
>> the
>> local CPU and allow the non pinned timers to be pulled onto a busy
>> CPU at
>> expiry time.
>
> Thanks for these patches. I am looking for saving power during video
> playback with our low power daemon. I use cgroup v2 isolation to keep
> some CPUs idle (CPU 0-11) and video is played on a single module (CPU
> 12-15).
>
> I have some kernelshark pictures at below link. The traces are
> collected with sched, timer and irq. With 6.6-rc5, you can see some
> timers still expires on CPUs which I want to keep idle. With timer
> patches added, they are mostly pulled to busy CPU. 
>
> https://imgur.com/a/8nF5OoP
>
> I can share the .dat files, but they are too big to attach here.

Thanks a lot for testing! The images are totally fine (at least for
me). As there are still some issues in v8, I'll have to post a new
version...

Thanks,

	Anna-Maria