CpuSet Feature While Using Upmpdcli

CpuSet Feature While Using Upmpdcli - Printable Version

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RE: CpuSet Feature While Using Upmpdcli - PeteCallaghan - 09-Nov-2020

(11-Oct-2020, 05:25 PM)agent_kith Wrote:
(09-Oct-2020, 06:22 PM)PeteCallaghan Wrote: There seemed to be multiple mpd processes, so a loop was needed to catch them all:

Code:
pids=$(pgrep mpd) for pid in $pids do chrt -r -p 99 $pid cset proc --move --threads --toset=user --force --pid=$pid done
In theory you don't have to do this, just find the main PID, and the --threads option will move all threads to the CPUSet.

But, that's really dependent on how MPD works.. e.g. if MPD fork a thread on playback, there is always a chance this script will not work.. i.e. MPD starts, and the script moves the threads to the CPU Set, and when you play, MPD fork another thread, this is not trapped by the script as it happens after the fact..

There's prob a way to fix this, but I havn't investigate deeply enough yet... The current script, while brutally simple, actually yield quite a good audio improvement.. But I've mostly tested this in LMS and Squeezelite..

Please continue to explore this and let me know your progress, I'll incorporate your work into the next release too.

Some progress. I now have a crude but reliable process for applying the script after a reboot.

I add a line to crontab that waits for 10 minutes after a reboot and then applies the script:

Code:
#crontab-e

@reboot sleep 600; sh [path to script file]/mpdpriority.sh

I have not experimented with shorter sleep times, as this seems pretty reliable.

I'll research how to follow up your point about forked threads, to see if I can find any and see if they are allocated to the correct CPU set

RE: CpuSet Feature While Using Upmpdcli - PeteCallaghan - 14-Nov-2020

I made an error in my script. The pgrep was returning both mpd and upmpdcli processes because it was matching 'mpd' in both process names.

This version matches exactly 'mpd' and only finds one pid, using the '-x' option in pgrep

Code:
pids=$(pgrep -x mpd)

for pid in $pids

do

chrt -r -p 99 $pid

cset proc --move  --threads --toset=user --force --pid=$pid

done

I am running upmpdcli as the music server, which uses mpd as the player.

Using cpuset I have successfully got both mpd and upmpdcli running in the user cpuset, and mpd running with RT priority, which sounds pretty good.

However, I suspect that it would be beneficial to run mpd alone in the user cpuset, with upmpdcli in the system cpuset.

However I can't figure out how to achieve this. Any suggestions?

I could de-select upmpdcli as the music server and use mpd instead, but then I would need to lanch upmpdcli outside snakeoil. What would be the best way to do this?

RE: CpuSet Feature While Using Upmpdcli - PeteCallaghan - 16-Nov-2020

(14-Nov-2020, 07:20 PM)PeteCallaghan Wrote: I am running upmpdcli as the music server, which uses mpd as the player.

Using cpuset I have successfully got both mpd and upmpdcli running in the user cpuset, and mpd running with RT priority, which sounds pretty good.

However, I suspect that it would be beneficial to run mpd alone in the user cpuset, with upmpdcli in the system cpuset.

However I can't figure out how to achieve this. Any suggestions?

I could de-select upmpdcli as the music server and use mpd instead, but then I would need to lanch upmpdcli outside snakeoil. What would be the best way to do this?

Is it possible to configure SO so that mpd is the music server and upmpdcli is the music client?

I've tried setting mpd as server but upmpdcli is not available to configure as music client