From 23dd74db02d75579d8d4eb0b88c7ad119e782269 Mon Sep 17 00:00:00 2001 From: Tvrtko Ursulin Date: Fri, 29 Apr 2022 11:04:13 +0100 Subject: [PATCH] drm/i915: Enable THP on Icelake and beyond We have a statement from HW designers that the GPU read regression when using 2M pages was fixed from Icelake onwards, which was also confirmed by bencharking Eero did last year: """ When IOMMU is disabled, enabling THP causes following perf changes on TGL-H (GT1): 10-15% SynMark Batch[0-3] 5-10% MemBW GPU texture, SynMark ShMapVsm 3-5% SynMark TerrainFly* + Geom* + Fill* + CSCloth + Batch4 1-3% GpuTest Triangle, SynMark TexMem* + DeferredAA + Batch[5-7] + few others -7% MemBW GPU blend In the above 3D benchmark names, * means all the variants of tests with the same prefix. For example "SynMark TexMem*", means both TexMem128 & TexMem512 tests in the synthetic (Intel internal) SynMark test suite. In the (public, but proprietary) GfxBench & GLB(enchmark) test suites, there are both onscreen and offscreen variants of each test. Unless explicitly stated otherwise, numbers are for both variants. All tests are run with FullHD monitor. All tests are fullscreen except for GLB and GpuTest ones, which are run in 1/2 screen window (GpuTest triangle is run both in fullscreen and 1/2 screen window). """ Since the only regression is MemBW GPU blend, against many more gains, it sounds it is time to enable THP on Gen11+. Signed-off-by: Tvrtko Ursulin References: https://gitlab.freedesktop.org/drm/intel/-/issues/430 Cc: Joonas Lahtinen Cc: Matthew Auld Cc: Eero Tamminen Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20220429100414.647857-1-tvrtko.ursulin@linux.intel.com --- drivers/gpu/drm/i915/gem/i915_gemfs.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gemfs.c b/drivers/gpu/drm/i915/gem/i915_gemfs.c index ee87874..c5a6bbc 100644 --- a/drivers/gpu/drm/i915/gem/i915_gemfs.c +++ b/drivers/gpu/drm/i915/gem/i915_gemfs.c @@ -28,12 +28,14 @@ int i915_gemfs_init(struct drm_i915_private *i915) * * One example, although it is probably better with a per-file * control, is selecting huge page allocations ("huge=within_size"). - * However, we only do so to offset the overhead of iommu lookups - * due to bandwidth issues (slow reads) on Broadwell+. + * However, we only do so on platforms which benefit from it, or to + * offset the overhead of iommu lookups, where with latter it is a net + * win even on platforms which would otherwise see some performance + * regressions such a slow reads issue on Broadwell and Skylake. */ opts = NULL; - if (i915_vtd_active(i915)) { + if (GRAPHICS_VER(i915) >= 11 || i915_vtd_active(i915)) { if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { opts = huge_opt; drm_info(&i915->drm, @@ -41,7 +43,10 @@ int i915_gemfs_init(struct drm_i915_private *i915) opts); } else { drm_notice(&i915->drm, - "Transparent Hugepage support is recommended for optimal performance when IOMMU is enabled!\n"); + "Transparent Hugepage support is recommended for optimal performance%s\n", + GRAPHICS_VER(i915) >= 11 ? + " on this platform!" : + " when IOMMU is enabled!"); } } -- 2.7.4