From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E288C4338F for ; Wed, 28 Jul 2021 16:16:37 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 38E7160F0F for ; Wed, 28 Jul 2021 16:16:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 38E7160F0F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1EF8C6E424; Wed, 28 Jul 2021 16:16:34 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7990F6E20E; Wed, 28 Jul 2021 16:16:32 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10059"; a="212423177" X-IronPort-AV: E=Sophos;i="5.84,276,1620716400"; d="scan'208";a="212423177" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jul 2021 09:16:27 -0700 X-IronPort-AV: E=Sophos;i="5.84,276,1620716400"; d="scan'208";a="566922494" Received: from hseyedro-mobl.amr.corp.intel.com (HELO intel.com) ([10.213.174.18]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jul 2021 09:16:26 -0700 Date: Wed, 28 Jul 2021 12:16:25 -0400 From: Rodrigo Vivi To: Tvrtko Ursulin Message-ID: References: <20210728141249.357067-1-tvrtko.ursulin@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210728141249.357067-1-tvrtko.ursulin@linux.intel.com> Subject: Re: [Intel-gfx] [PATCH] drm/i915: Use Transparent Hugepages when IOMMU is enabled X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Chris Wilson , Matthew Auld , Eero Tamminen Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Jul 28, 2021 at 03:12:49PM +0100, Tvrtko Ursulin wrote: > From: Tvrtko Ursulin > > Usage of Transparent Hugepages was disabled in 9987da4b5dcf > ("drm/i915: Disable THP until we have a GPU read BW W/A"), but since it > appears majority of performance regressions reported with an enabled IOMMU > can be almost eliminated by turning them on, lets do that by adding a > couple of Kconfig options. > > To err on the side of safety we keep the current default in cases where > IOMMU is not active, and only when it is default to the "huge=within_size" > mode. Although there probably would be wins to enable them throughout, > more extensive testing across benchmarks and platforms would need to be > done. > > With the patch and IOMMU enabled my local testing on a small Skylake part > shows OglVSTangent regression being reduced from ~14% to ~2%. > > References: b901bb89324a ("drm/i915/gemfs: enable THP") > References: 9987da4b5dcf ("drm/i915: Disable THP until we have a GPU read BW W/A") > References: https://gitlab.freedesktop.org/drm/intel/-/issues/430 > Co-developed-by: Chris Wilson > Signed-off-by: Chris Wilson > Cc: Joonas Lahtinen > Cc: Matthew Auld > Cc: Eero Tamminen > Cc: Tvrtko Ursulin > Signed-off-by: Tvrtko Ursulin > --- > drivers/gpu/drm/i915/Kconfig.profile | 46 +++++++++++++++++++++++++++ > drivers/gpu/drm/i915/gem/i915_gemfs.c | 11 +++++-- > 2 files changed, 55 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/Kconfig.profile b/drivers/gpu/drm/i915/Kconfig.profile > index 39328567c200..c64c3d39a0f9 100644 > --- a/drivers/gpu/drm/i915/Kconfig.profile > +++ b/drivers/gpu/drm/i915/Kconfig.profile > @@ -119,3 +119,49 @@ config DRM_I915_TIMESLICE_DURATION > /sys/class/drm/card?/engine/*/timeslice_duration_ms > > May be 0 to disable timeslicing. > + > +choice > + prompt "Transparent Hugepage Support (native)" > + default DRM_I915_THP_NATIVE_NEVER > + help > + Select the preferred method for allocating from Transparent Hugepages > + when IOMMU is not enabled. > + > + config DRM_I915_THP_NATIVE_NEVER > + bool "Never" > + > + config DRM_I915_THP_NATIVE_WITHIN > + bool "Within" > + > + config DRM_I915_THP_NATIVE_ALWAYS > + bool "Always" > +endchoice > + > +config DRM_I915_THP_NATIVE > + string > + default "always" if DRM_I915_THP_NATIVE_ALWAYS > + default "within_size" if DRM_I915_THP_NATIVE_WITHIN > + default "never" if DRM_I915_THP_NATIVE_NEVER > + > +choice > + prompt "Transparent Hugepage Support (IOMMU)" > + default DRM_I915_THP_IOMMU_WITHIN > + help > + Select the preferred method for allocating from Transparent Hugepages > + with IOMMU active. > + > + config DRM_I915_THP_IOMMU_NEVER > + bool "Never" > + > + config DRM_I915_THP_IOMMU_WITHIN > + bool "Within" > + > + config DRM_I915_THP_IOMMU_ALWAYS > + bool "Always" > +endchoice > + > +config DRM_I915_THP_IOMMU > + string > + default "always" if DRM_I915_THP_IOMMU_ALWAYS > + default "within_size" if DRM_I915_THP_IOMMU_WITHIN > + default "never" if DRM_I915_THP_IOMMU_NEVER > diff --git a/drivers/gpu/drm/i915/gem/i915_gemfs.c b/drivers/gpu/drm/i915/gem/i915_gemfs.c > index 5e6e8c91ab38..b71d2b2d2ada 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gemfs.c > +++ b/drivers/gpu/drm/i915/gem/i915_gemfs.c > @@ -13,8 +13,11 @@ > > int i915_gemfs_init(struct drm_i915_private *i915) > { > + char thp_native[] = "huge=" CONFIG_DRM_I915_THP_NATIVE; > + char thp_iommu[] = "huge=" CONFIG_DRM_I915_THP_IOMMU; > struct file_system_type *type; > struct vfsmount *gemfs; > + char *opts; > > type = get_fs_type("tmpfs"); > if (!type) > @@ -26,15 +29,19 @@ 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"). > - * Currently unused due to bandwidth issues (slow reads) on Broadwell+. > + * However, we only do so to offset the overhead of iommu lookups > + * due to bandwidth issues (slow reads) on Broadwell+. > */ > + opts = intel_vtd_active() ? thp_iommu : thp_native; at first sight I got confused on why we where having to configs, then very few drivers using the mount option there, so it took me a few minutes to realize it... but I know understood the goal... Reviewed-by: Rodrigo Vivi > > - gemfs = kern_mount(type); > + gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, opts); > if (IS_ERR(gemfs)) > return PTR_ERR(gemfs); > > i915->mm.gemfs = gemfs; > > + drm_info(&i915->drm, "Transparent Hugepage mode '%s'", opts); > + > return 0; > } > > -- > 2.30.2 > _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx