Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...

franck

Hi guys, I just realised that the retroarch core game port I wrote was slow on pi, because my pi was configured with a default HDMI mode of 1920*1080/50Hz.
In this resolution the pi 3 is not able to refresh the screen fast enough and the vsync is always broken...

I uncommented /boot/config.txt parameters hdmi_group=1 hdmi_mode=4 and rebooted and that fixed my problem, and the game is now totally fluid.

You can check your current mode with the fbset command:

pi@raspberrypi:~ $ fbset -s

mode "1280x720"
geometry 1280 720 1280 720 16
timings 0 0 0 0 0 0 0
rgba 5/11,6/5,5/0,0/16
endmode

I wanted to get feedback on this, because it seems very easy to me to get your pi wrongly configured and simply thinking this is a normal (slow) speed.

Shouldn't there be some kind of warning popup displayed, when trying to run a low resolution 60hz core in the 1920*1080 50Hz mode ?

dankcushions

@franck your games issue is not a generic one :) libretro cores run fine at 1080p on a pi3. n64 and dreamcast are bespokely configured to use a lower framebuffer.

also the default for retropie is 1080p + 60hz for me, though it may depend on your TVs hdmi handshake.

franck

@dankcushions said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:

@franck your games issue is not a generic one :) libretro cores run fine at 1080p on a pi3. n64 and dreamcast are bespokely configured to use a lower framebuffer.
also the default for retropie is 1080p + 60hz for me, though it may depend on your TVs hdmi handshake.

I spotted the same problem on the example core advanced_tests_libretro "1B test" from the libretro/libretro-samples and on a netplay test core doing absolutely nothing... So it's not dependant of the core on my pi. Indeed it's very easy not to spot the vsync issue (except in the core logs) depending on what is displayed on the screen. With a scrolltext or some vertical line scrolling in advanced_tests_libretro it's easy to see it.

dankcushions

@franck said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:

@dankcushions said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:
@franck your games issue is not a generic one :) libretro cores run fine at 1080p on a pi3. n64 and dreamcast are bespokely configured to use a lower framebuffer.
also the default for retropie is 1080p + 60hz for me, though it may depend on your TVs hdmi handshake.
I spotted the same problem on the example core advanced_tests_libretro "1B test" from the libretro/libretro-samples and on a netplay test core doing absolutely nothing... So it's not dependant of the core on my pi. Indeed it's very easy not to spot the vsync issue (except in the core logs) depending on what is displayed on the screen. With a scrolltext or some vertical line scrolling in advanced_tests_libretro it's easy to see it.

looks like you're running your own build of retroarch in X? have you tried with the default retropie image?

franck

@dankcushions said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:

looks like you're running your own build of retroarch in X? have you tried with the default retropie image?

I have the same behavior using the retropie image, I was using my own compiled version to have the latest version in the bug report.

dankcushions

@franck said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:

@dankcushions said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:

looks like you're running your own build of retroarch in X? have you tried with the default retropie image?

I have the same behavior using the retropie image, I was using my own compiled version to have the latest version in the bug report.

it must be your tv, then. libretro advanced tests is running at 60 fps, so if your tv is running at 50hz, with v-sync on you would be getting a stutter. anyone with a tv running at 60hz (which retropie does fine for me and most) should not get such an issue.

franck

@dankcushions said in Default HDMI mode can get you an (undetected!) slow performance on Raspberry pi...:

it must be your tv, then. libretro advanced tests is running at 60 fps, so if your tv is running at 50hz, with v-sync on you would be getting a stutter. anyone with a tv running at 60hz (which retropie does fine for me and most) should not get such an issue.

I have a Philips BDM4065UC/00 monitor, but that's a bit my point:
the default setting is 1920*1080 running at 50Hz. so If I don't realise that and change it, I get a poor performance...