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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id A1032C433EF for ; Mon, 22 Nov 2021 09:43:22 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E8BA489C0D; Mon, 22 Nov 2021 09:43:21 +0000 (UTC) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTPS id A53AF6E092; Mon, 22 Nov 2021 09:43:20 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10175"; a="221977718" X-IronPort-AV: E=Sophos;i="5.87,254,1631602800"; d="scan'208";a="221977718" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2021 01:43:20 -0800 X-IronPort-AV: E=Sophos;i="5.87,254,1631602800"; d="scan'208";a="508465571" Received: from aalazizi-mobl1.amr.corp.intel.com (HELO [10.213.249.159]) ([10.213.249.159]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Nov 2021 01:43:18 -0800 Message-ID: <4d5deeb3-1eb9-f374-6729-1fe03d5e774e@linux.intel.com> Date: Mon, 22 Nov 2021 09:43:15 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.1 Content-Language: en-US To: Matthew Auld , intel-gfx@lists.freedesktop.org References: <20211028092638.3142258-1-matthew.auld@intel.com> <20211028092638.3142258-2-matthew.auld@intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc In-Reply-To: <20211028092638.3142258-2-matthew.auld@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Intel-gfx] [PATCH v2 2/2] drm/i915/gtt: stop caching the scratch page 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: =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= , dri-devel@lists.freedesktop.org, Chris Wilson Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 28/10/2021 10:26, Matthew Auld wrote: > Normal users shouldn't be hitting this, likely this would indicate a > userspace bug. So don't bother caching, which should be safe now that we > manually flush the page. Could this have a performance impact if "things" overfetch often enough in normal operation? Regards, Tvrtko > Suggested-by: Chris Wilson > Signed-off-by: Matthew Auld > Cc: Thomas Hellström > Cc: Chris Wilson > Cc: Ramalingam C > Reviewed-by: Thomas Hellström > --- > drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c > index 8af2f709571c..9966e9dc5218 100644 > --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c > +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c > @@ -651,7 +651,7 @@ static int gen8_init_scratch(struct i915_address_space *vm) > > vm->scratch[0]->encode = > gen8_pte_encode(px_dma(vm->scratch[0]), > - I915_CACHE_LLC, pte_flags); > + I915_CACHE_NONE, pte_flags); > > for (i = 1; i <= vm->top; i++) { > struct drm_i915_gem_object *obj; > @@ -667,7 +667,7 @@ static int gen8_init_scratch(struct i915_address_space *vm) > } > > fill_px(obj, vm->scratch[i - 1]->encode); > - obj->encode = gen8_pde_encode(px_dma(obj), I915_CACHE_LLC); > + obj->encode = gen8_pde_encode(px_dma(obj), I915_CACHE_NONE); > > vm->scratch[i] = obj; > } >