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=-15.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 ACB6EC433EF for ; Fri, 3 Sep 2021 12:48:06 +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 75A4F61057 for ; Fri, 3 Sep 2021 12:48:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 75A4F61057 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.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 4D00C6E88B; Fri, 3 Sep 2021 12:48:00 +0000 (UTC) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by gabe.freedesktop.org (Postfix) with ESMTPS id A59426E88A; Fri, 3 Sep 2021 12:47:58 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10095"; a="206532541" X-IronPort-AV: E=Sophos;i="5.85,265,1624345200"; d="scan'208";a="206532541" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2021 05:47:58 -0700 X-IronPort-AV: E=Sophos;i="5.85,265,1624345200"; d="scan'208";a="500348132" Received: from ojcasey-mobl.ger.corp.intel.com (HELO [10.213.195.251]) ([10.213.195.251]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2021 05:47:54 -0700 To: Daniel Vetter Cc: intel-gfx , dri-devel , Tvrtko Ursulin , Chris Wilson , Joonas Lahtinen , Matthew Auld , Eero Tamminen , Rodrigo Vivi References: <20210729133420.770672-1-tvrtko.ursulin@linux.intel.com> <20210729133420.770672-2-tvrtko.ursulin@linux.intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: Date: Fri, 3 Sep 2021 13:47:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Intel-gfx] [PATCH 2/2] 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 29/07/2021 15:06, Daniel Vetter wrote: > On Thu, Jul 29, 2021 at 3:34 PM 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 just do that. >> >> 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% (IOMMU on versus >> IOMMU off) to ~2% (same comparison but with THP on). >> >> v2: >> * Add Kconfig dependency to transparent hugepages and some help text. >> * Move to helper for easier handling of kernel build options. >> >> v3: >> * Drop Kconfig. (Daniel) >> >> 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 >> Cc: Rodrigo Vivi >> Cc: Daniel Vetter >> Signed-off-by: Tvrtko Ursulin >> Reviewed-by: Rodrigo Vivi # v1 > > On both patches: Acked-by: Daniel Vetter Eero's testing results at https://gitlab.freedesktop.org/drm/intel/-/issues/430 are looking good - seem to show this to be a net win for at least Gen9 and Gen12 platforms. Is the ack enough to merge in this case or I should look for an r-b as well? Regards, Tvrtko >> --- >> drivers/gpu/drm/i915/gem/i915_gemfs.c | 22 +++++++++++++++++++--- >> 1 file changed, 19 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/gem/i915_gemfs.c b/drivers/gpu/drm/i915/gem/i915_gemfs.c >> index 5e6e8c91ab38..dbdbdc344d87 100644 >> --- a/drivers/gpu/drm/i915/gem/i915_gemfs.c >> +++ b/drivers/gpu/drm/i915/gem/i915_gemfs.c >> @@ -6,7 +6,6 @@ >> >> #include >> #include >> -#include >> >> #include "i915_drv.h" >> #include "i915_gemfs.h" >> @@ -15,6 +14,7 @@ int i915_gemfs_init(struct drm_i915_private *i915) >> { >> struct file_system_type *type; >> struct vfsmount *gemfs; >> + char *opts; >> >> type = get_fs_type("tmpfs"); >> if (!type) >> @@ -26,10 +26,26 @@ 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+. >> */ >> >> - gemfs = kern_mount(type); >> + opts = NULL; >> + if (intel_vtd_active()) { >> + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { >> + static char huge_opt[] = "huge=within_size"; /* r/w */ >> + >> + opts = huge_opt; >> + drm_info(&i915->drm, >> + "Transparent Hugepage mode '%s'\n", >> + opts); >> + } else { >> + drm_notice(&i915->drm, >> + "Transparent Hugepage support is recommended for optimal performance when IOMMU is enabled!\n"); >> + } >> + } >> + >> + gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, opts); >> if (IS_ERR(gemfs)) >> return PTR_ERR(gemfs); >> >> -- >> 2.30.2 >> > >