dmd-play - slow, causing ES lagginess

[DaveBullet1050]

Each invocation of dmd-play on ES events (game-selected and system-selected) takes about 1.6 seconds to import all the required libraries on slower platforms (such as Pi 3B+)

I suggest you allow dmd-play to also run as a service, where a TCP socket can be used to send a command line, thus avoiding constant invocation.

This speeds up marquee changes considerably. i.e., 5Kb 128x32 PNG marquee would take ~ 1.9 seconds to change, whereas a socket based notification with an already running script takes < 0.2 seconds.

A potential solution to avoid having to rework the command line argument parsing code:

dmd-play <current arguments>
or
dmd-play -lp <port>

where -lp stands for "listener port". This could default to 6788 (i.e. one beside dmd_real assuming no dmd_simulator clash)

First example = current state (interactively play the clock, file etc....)

2nd example - TCP socket opened to receive requests (same command line support), eg:
Run as daemon / service
dmd-play -lp 6788 &
then as client:
echo -n "-f /userdata/system/dmd/games/mame/outrun.gif" | nc -w1 127.0.0.1 6788

[nadenislamarre]

looks like more a complex hack.
the good solution imh would be to remove numpy which is used only for 1 function (but which takes a lot of time to import)

[DaveBullet1050]

Fair point about the hackiness. However I prefer to see it as a service wrapper :) Not knowing python makes one economical on breaking change (doesn't make that good design though - noted).

I removed numpy import and it went from 1.5 seconds to 0.7 seconds. I still think there is a latency issue to address for navigation and also potentially a concurrency / laggy processing issue playing marquees from 3 navigations ago - benefited from being aborted (connection closed gracefully) via SIGINT or similar.

I have a solution on my system, just thought I'd share the problem. It may be waaaay down the priority list and not an issue reported by anyone else. So happy if you close it.

[nadenislamarre]

do you have a pr so that i can see ?

[DaveBullet1050]

Sorry github is rather new to me. I realise I need to fork off master branch? then make my changes, then create a PR from that?

As the core of the change is dmd-play

dmd-play.txt

It works just the same as previously - i.e. pass in -f, -t command line arguments and it will run interactively then end

However - if you call it with
dmd-play -lp <port_number>

Then it starts a socket to listen for the command line. Send with something like:

echo -n "-f /userdata/system/dmd/games/mame/pacland.png" | nc -c -w1 127.0.0.1 6788

I have a script which combines the SIGINT signal to the PID (i.e. raises an exception which stops playing the current GIF / animation / video) then echoes the new command line above. Seems to work well. I've also created a new service file /usr/share/batocera/services/dmd_play to startup /shutdown. as dmd_play is dependent on dmdserver running (there is no retry to connect), I just hope batocera observes the startup order of services listed in batocera.conf

I've attached dmd-play only above. I know this is not the right code approval/merge process, but the code isn't ready for a PR (i.e. I will need to do a lot more testing, remove some debug statements, there's a hard coded path hack in here etc.... Testing of all other methods (countdown, text etc...)

Oh - you'll also notice a colour cycle and speed option when displaying the clock.

If you think it is worthwhile, then I can create a PR

[DaveBullet1050]

I think I'm ready for a PR... when I work out the right way to do it :)

Anyway - dmd-play now uses shlex to parse sys.argv to ensure " delimited marquee filenames with spaces, special characters are not split up as separate arguments.

I've also added a /usr/share/batocera/services/dmd_play script so it can be run as a service.

Batocera not having the overhead of systemd daemon management, means there's little in the way of monitoring and restart of failed services.... not that they should fail, but there is no intelligence in restarting dmdserver or dmd-play processes should they die.

I also have created custom game-selected, system-selected, screensaver-start and screensaver-stop custom event scripts to integrate with the dmd-play server. They Batocera supplied scripts may work (I might do some testing) if they simply are tweaked to send via socket and not launch dmd-play instances.

[nadenislamarre]

i've tried to make it work. i managed to make it work one time.
i get the idea.
but it misses integration, really not easy to make it work.

[nadenislamarre]

in fact i think the best is to write dmd-play in c