From: Kieran Kunhya <kierank@obe.tv>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] ffmpeg appears to be wasting CPU time
Date: Fri, 7 Apr 2023 17:15:56 +0100
Message-ID: <CAK+ULv7=YMZBS3LnKf6Rra5jEM-fQUP95vY_iUzNcdLmshoBUA@mail.gmail.com> (raw)
In-Reply-To: <b5d2c662-05ab-507d-70f9-38e691193da5@davyandbeth.com>
On Fri, 7 Apr 2023 at 05:03, Davy Durham <ddurham@davyandbeth.com> wrote:
> After furiously digging through the ffmpeg code (particularly in older
> versions that also exhibit the problem, but where the code is simpler) I
> have found no reason for there to be wasted CPU time.
>
> In my travels, I frustratingly noticed that sometime the problem would
> mysteriously vanish. And, long story short, I believe I've been chasing
> a phantom. If, on my local machine w/ 8 cores, I start a process that
> simply spins one CPU, the problem vanishes--that is, now whether running
> ffmpeg at full speed or with a read rate limit, the cumulative CPU
> reported by 'time' is nearly** the same, as one would expect it to be.
>
Are you sure this isn't just your CPU governor and/or the effects of
frequency scaling/C-states?
Kieran
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next prev parent reply other threads:[~2023-04-07 16:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-30 8:20 Davy Durham
2023-04-07 4:03 ` Davy Durham
2023-04-07 16:15 ` Kieran Kunhya [this message]
2023-04-07 20:26 ` Davy Durham
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