Date: Wed, 23 Nov 2022 07:00:14 +0900 From: Tomoaki AOKI <junchoon@dec.sakura.ne.jp> To: Hans Petter Selasky <hps@selasky.org> Cc: mike tancsa <mike@sentex.net>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: ULE realtime scheduler advice needed Message-ID: <20221123070014.71f5cc4f1d86cb4d4c0f6bf6@dec.sakura.ne.jp> In-Reply-To: <1a404155-4ca9-4e88-4c40-5407c2ae52a9@selasky.org> References: <7ad10a5e-29d6-aaef-25cf-407d65f056cc@selasky.org> <8d8c4b03-323a-8e4d-44fd-e47749d2fd85@sentex.net> <1a404155-4ca9-4e88-4c40-5407c2ae52a9@selasky.org>
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On Tue, 22 Nov 2022 22:38:04 +0100
Hans Petter Selasky <hps@selasky.org> wrote:
> On 11/22/22 20:28, mike tancsa wrote:
> > On 11/17/2022 11:47 PM, Hans Petter Selasky wrote:
> >> Hi,
> >>
> >> I'm doing some work with audio and have noticed some problems with the
> >> ULE scheduler. I have a program that generate audio based on
> >> key-presses. When no keys are pressed, the load is near 0%, but as
> >> soon as you start pressing keys, the load goes maybe to 80% of a CPU
> >> core. This program I run with rtprio 8 xxx. The issue I observe or
> >> hear actually, is that it takes too long until the scheduler grasps
> >> that this program needs it's own CPU core and stops time-sharing the
> >> program. When I however use cpuset -l xxx rtprio 8 yyy everything is
> >> good, and the program outputs realtime audio in-time.
> >>
> >> Or is this perhaps a CPU frequency stepping issue?
> >>
> >> Any advice on where to look?
> >>
> > A long shot, but I am curious if by chance you have hwpstate_intel for
> > your cpu frequency driver. If so, does setting
> > dev.hwpstate_intel.0.epp=0 make any difference ?
> >
>
> Yes, I have four of those, set to 50 by default. Let me try.
>
> --HPS
FYI: I habitally run below manually (as root) when I'm on AC powerline.
sysctl -aN | fgrep dev.hwpstate | fgrep epp | while read OID ; do ; \
sysctl ${OID}=0 ; done
--
Tomoaki AOKI <junchoon@dec.sakura.ne.jp>
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