Created attachment 110670 [details] dmesg ==System Environment== -------------------------- Regression: not sure Non-working platforms: BYT ==kernel== -------------------------- drm-intel-nightly/34d267c2ba9c0845432baf959a2c4deed87f3ee4 drm-intel-fixes/b0616c5306b342ceca07044dbc4f917d95c4f825 drm-intel-next-queued/b05ddd4dfb6303ee9dde359ec913aa7a918fd813 ==Bug detailed description== ----------------------------- It fails 1 in 5 runs on BYT with -nightly kernel. IGT-Version: 1.8-gf333981 (x86_64) (Linux: 3.18.0_drm-intel-nightly_34d267_20141210_debug+ x86_64) gem_cs_prefetch: 100% Test suceeded, cleanup up - this might take a while. real 13m20.823s user 0m7.349s sys 9m17.419s root@x-bytm02:/GFX/Test/Intel_gpu_tools/intel-gpu-tools/tests# time ./gem_cs_prefetch IGT-Version: 1.8-gf333981 (x86_64) (Linux: 3.18.0-rc7_drm-intel-next-queued_b05ddd_20141210+ x86_64) gem_cs_prefetch: 100% Test suceeded, cleanup up - this might take a while. real 0m48.062s user 0m4.316s sys 0m43.576s root@x-bytm02:/GFX/Test/Intel_gpu_tools/intel-gpu-tools/tests# time ./gem_cs_prefetch IGT-Version: 1.8-gf333981 (x86_64) (Linux: 3.18.0-rc7_drm-intel-fixes_b0616c_20141210+ x86_64) gem_cs_prefetch: 100% Test suceeded, cleanup up - this might take a while. real 0m32.991s user 0m4.115s sys 0m28.194s Reproduce steps: ------------------------- 1. ./gem_cs_prefetch
Massive increase in system time -> kswapd overhead? Could it be bisected? Could you grab a perf profile? (Just running the loop under perf will be enough as the slow run is so much slower it will dominate the profile.)
Run 5 cycles on latest nightly kernel, It doesn't have this issue. It takes about 49s, set worksforme, if I meet it again, then update. root@x-bytm02:/GFX/Test/Intel_gpu_tools/intel-gpu-tools/tests# time ./gem_cs_prefetch IGT-Version: 1.8-gf333981 (x86_64) (Linux: 3.18.0_drm-intel-nightly_b4c227_20141212+ x86_64) gem_cs_prefetch: 100% Test suceeded, cleanup up - this might take a while. real 0m48.792s user 0m4.094s sys 0m44.526s
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