Nyaaori/gamescope
1
0
Fork 0
Code Issues Pull requests Projects Releases 1 Packages Wiki Activity

vblankmanager: Scale vblank redzone against target refresh

Browse source 
Fixes frametimings at 4K@30Hz
This commit is contained in:
Joshua Ashton 2022-07-27 10:46:37 +00:00
parent cd1fed6c2d
commit 312a616501
1 changed files with 11 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
src/vblankmanager.cpp
View file

@ -68,6 +68,12 @@ void vblankThreadRun( void )
const uint64_t nsecInterval = 1'000'000'000ul / refresh;
const uint64_t drawTime = g_uVblankDrawTimeNS;
// The redzone is relative to 60Hz, scale it by our
// target refresh so we don't miss submitting for vblank in DRM.
// (This fixes 4K@30Hz screens)
const uint64_t nsecToSec = 1'000'000'000ul;
const uint64_t redZone = ( g_uVblankDrawBufferRedZoneNS * 60 * nsecToSec ) / ( refresh * nsecToSec );
// This is a rolling average when drawTime < rollingMaxDrawTime,
// and a a max when drawTime > rollingMaxDrawTime.
// This allows us to deal with spikes in the draw buffer time very easily.
@ -76,24 +82,24 @@ void vblankThreadRun( void )
// we get back into a good state and then regress again.
// If we go over half of our deadzone, be more defensive about things.
if ( int64_t(drawTime) - int64_t(g_uVblankDrawBufferRedZoneNS / 2) > int64_t(rollingMaxDrawTime) )
if ( int64_t(drawTime) - int64_t(redZone / 2) > int64_t(rollingMaxDrawTime) )
rollingMaxDrawTime = drawTime;
else
rollingMaxDrawTime = ( ( alpha * rollingMaxDrawTime ) + ( range - alpha ) * drawTime ) / range;
// If we need to offset for our draw more than half of our vblank, something is very wrong.
// Clamp our max time to half of the vblank if we can.
rollingMaxDrawTime = std::min( rollingMaxDrawTime, nsecInterval - g_uVblankDrawBufferRedZoneNS );
rollingMaxDrawTime = std::min( rollingMaxDrawTime, nsecInterval - redZone );
g_uRollingMaxDrawTime = rollingMaxDrawTime;
uint64_t offset = rollingMaxDrawTime + g_uVblankDrawBufferRedZoneNS;
uint64_t offset = rollingMaxDrawTime + redZone;
#ifdef VBLANK_DEBUG
// Debug stuff for logging missed vblanks
static uint64_t vblankIdx = 0;
static uint64_t lastDrawTime = g_uVblankDrawTimeNS;
static uint64_t lastOffset = g_uVblankDrawTimeNS + g_uVblankDrawBufferRedZoneNS;
static uint64_t lastOffset = g_uVblankDrawTimeNS + redZone;
if ( vblankIdx++ % 300 == 0 || drawTime > lastOffset )
{
@ -101,7 +107,7 @@ void vblankThreadRun( void )
fprintf( stderr, " !! missed vblank " );
fprintf( stderr, "redZone: %.2fms decayRate: %lu%% - rollingMaxDrawTime: %.2fms lastDrawTime: %.2fms lastOffset: %.2fms - drawTime: %.2fms offset: %.2fms\n",
g_uVblankDrawBufferRedZoneNS / 1'000'000.0,
redZone / 1'000'000.0,
g_uVBlankRateOfDecayPercentage,
rollingMaxDrawTime / 1'000'000.0,
lastDrawTime / 1'000'000.0,