SW setup: - Mesa git - X server git - modesetting driver - drm-tip kernel v4.14 (which has somewhat worse texture read perf than 4.13) - everything else: Ubuntu 16.04 (Unity/compiz) - whole system is using the Mesa git version, not just test programs Between following Mesa commits: 2017-11-13 257edb5b9aedc9fc5d5c13eb2f48a0c11d15456f glx/dri3: Fix passing renderType into glXCreateContext 2017-11-14 6ac2d16901927013393f873a34c717ece5014c1a i965/fs: Fix extract_i8/u8 to a 64-bit destination On 1-channel BSW (N3050 NUC), performance in all windowed/composited tests dropped very clearly. Drop scales directly with FPS, so it was largest in test with highest FPS: - 25-30% in GpuTest Triangle - 6-7% GLB 2.7 Egypt Same effect is seen also on BDW GT3, but it's much smaller, and even smaller on BDW GT2. -> I think the issue scales also depending on how memory bandwidth limited the GPU is. There's no change in fullscreen benchmarks, only in windowed / composited ones. From the Mesa change log between these commits, external BO and MOCS changes look most likely candinates. (Not bisecting this, just reporting it in hopes that somebody else can reproduce & bisect it.)
(In reply to Eero Tamminen from comment #0) > SW setup: > - Mesa git > - X server git > - modesetting driver > - drm-tip kernel v4.14 (which has somewhat worse texture read perf than 4.13) > - everything else: Ubuntu 16.04 (Unity/compiz) > - whole system is using the Mesa git version, not just test programs Mesa perf drop is visible also with drm-tip 4.13 kernel and ~2 months old X server git version.
It seems that some update on the Ubuntu side (compiz I assume) has fixed the huge windowed/composited benchmarks performance drop on BSW. -> original Mesa perf drop was some issue between it and (Ubuntu 16.04) Compiz? There was no change for BDW.
Since it dropped and came back, and it's been four months, we're not likely to look into this. Closing.
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