97ef806a53146837f6ca84a1b36763fb3bb67eaa - drm/sched: Add some scheduling quality unit tests

Fri, 17 Apr 2026 12:37:19 +0200

drm/sched: Add some scheduling quality unit testsTo make evaluating different scheduling policies easier (no need forexternal benchmarks) and perfectly repeatable, lets add some syntheticworkloads built upon mock scheduler unit test infrastructure.Focus is on two parallel clients (two threads) submitting different jobpatterns and logging their progress and some overall metrics. This isrepeated for both scheduler credit limit 1 and 2.Example test output: Normal and low: pct1 cps1 qd1; pct2 cps2 qd2 + 0ms: 0 0 0; 0 0 0 + 104ms: 100 1240 112; 100 1240 125 + 209ms: 100 0 99; 100 0 125 + 313ms: 100 0 86; 100 0 125 + 419ms: 100 0 73; 100 0 125 + 524ms: 100 0 60; 100 0 125 + 628ms: 100 0 47; 100 0 125 + 731ms: 100 0 34; 100 0 125 + 836ms: 100 0 21; 100 0 125 + 939ms: 100 0 8; 100 0 125 + 1043ms: ; 100 0 120 + 1147ms: ; 100 0 107 + 1252ms: ; 100 0 94 + 1355ms: ; 100 0 81 + 1459ms: ; 100 0 68 + 1563ms: ; 100 0 55 + 1667ms: ; 100 0 42 + 1771ms: ; 100 0 29 + 1875ms: ; 100 0 16 + 1979ms: ; 100 0 3 0: prio=normal sync=0 elapsed_ms=1015ms (ideal_ms=1000ms) cycle_time(min,avg,max)=134,222,978 us latency_time(min,avg,max)=134,222,978us 1: prio=low sync=0 elapsed_ms=2009ms (ideal_ms=1000ms) cycle_time(min,avg,max)=134,215,806 us latency_time(min,avg,max)=134,215,806 usThere we have two clients represented in the two respective columns, withtheir progress logged roughly every 100 milliseconds. The metrics are: - pct - Percentage progress of the job submit part - cps - Cycles per second - qd - Queue depth - number of submitted unfinished jobsThe cycles per second metric is inherent to the fact that workloadpatterns are a data driven cycling sequence of: - Submit 1..N jobs - Wait for Nth job to finish (optional) - Sleep (optional) - Repeat from startIn this particular example we have a normal priority and a low priorityclient both spamming the scheduler with 8ms jobs with no sync and nosleeping. Hence they build very deep queues and we can see how the lowpriority client is completely starved until the normal finishes.Note that the PCT and CPS metrics are irrelevant for "unsync" clientssince they manage to complete all of their cycles instantaneously.A different example would be: Heavy and interactive: pct1 cps1 qd1; pct2 cps2 qd2 + 0ms: 0 0 0; 0 0 0 + 106ms: 5 40 3; 5 40 0 + 209ms: 9 40 0; 9 40 0 + 314ms: 14 50 3; 14 50 0 + 417ms: 18 40 0; 18 40 0 + 522ms: 23 50 3; 23 50 0 + 625ms: 27 40 0; 27 40 1 + 729ms: 32 50 0; 32 50 0 + 833ms: 36 40 1; 36 40 0 + 937ms: 40 40 0; 40 40 0 + 1041ms: 45 50 0; 45 50 0 + 1146ms: 49 40 1; 49 40 1 + 1249ms: 54 50 0; 54 50 0 + 1353ms: 58 40 1; 58 40 0 + 1457ms: 62 40 0; 62 40 1 + 1561ms: 67 50 0; 67 50 0 + 1665ms: 71 40 1; 71 40 0 + 1772ms: 76 50 0; 76 50 0 + 1877ms: 80 40 1; 80 40 0 + 1981ms: 84 40 0; 84 40 0 + 2085ms: 89 50 0; 89 50 0 + 2189ms: 93 40 1; 93 40 0 + 2293ms: 97 40 0; 97 40 1In this case client one is submitting 3x 2.5ms jobs, waiting for the 3rdand then sleeping for 2.5ms (in effect causing 75% GPU load, minus theoverheads). Second client is submitting 1ms jobs, waiting for each tofinish and sleeping for 9ms (effective 10% GPU load). Here we can seethe PCT and CPS reflecting real progress.Signed-off-by: Tvrtko Ursulin Cc: Christian König Cc: Danilo Krummrich Cc: Matthew Brost Cc: Philipp Stanner Cc: Pierre-Eric Pelloux-Prayer Acked-by: Christian König Acked-by: Danilo Krummrich Tested-by: Vitaly Prosyak Signed-off-by: Philipp Stanner Link: https://patch.msgid.link/20260417103744.76020-5-tvrtko.ursulin@igalia.com List of files: /linux/drivers/gpu/drm/scheduler/tests/Makefile

5a99350794fec11faaed8a4b36a6931e696f672f - drm/sched: Add scheduler unit testing infrastructure and some basic tests

Mon, 24 Mar 2025 10:26:29 +0100

drm/sched: Add scheduler unit testing infrastructure and some basic testsImplement a mock scheduler backend and add some basic test to exercise thecore scheduler code paths.Mock backend (kind of like a very simple mock GPU) can either process jobsby tests manually advancing the "timeline" job at a time, or alternativelyjobs can be configured with a time duration in which case they getcompleted asynchronously from the unit test code.Core scheduler classes are subclassed to support this mock implementation.The tests added are just a few simple submission patterns.Signed-off-by: Tvrtko Ursulin Suggested-by: Philipp Stanner Cc: Christian König Cc: Danilo Krummrich Cc: Matthew Brost Cc: Philipp Stanner Acked-by: Christian König Signed-off-by: Philipp Stanner Link: https://patchwork.freedesktop.org/patch/msgid/20250324092633.49746-3-tvrtko.ursulin@igalia.com List of files: /linux/drivers/gpu/drm/scheduler/tests/Makefile

Changes in Makefile

97ef806a53146837f6ca84a1b36763fb3bb67eaa - drm/sched: Add some scheduling quality unit tests

5a99350794fec11faaed8a4b36a6931e696f672f - drm/sched: Add scheduler unit testing infrastructure and some basic tests