From patchwork Mon Apr 8 13:28:40 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 2408541 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork1.kernel.org (Postfix) with ESMTP id 868803FD1A for ; Mon, 8 Apr 2013 13:29:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4DE28E6250 for ; Mon, 8 Apr 2013 06:29:05 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (s16502780.onlinehome-server.info [87.106.93.118]) by gabe.freedesktop.org (Postfix) with ESMTP id 78111E5D16 for ; Mon, 8 Apr 2013 06:28:54 -0700 (PDT) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.73.22; Received: from arrandale.alporthouse.com (unverified [78.156.73.22]) by fireflyinternet.com (Firefly Internet (M2)) with ESMTP id 3464981-1500048 for multiple; Mon, 08 Apr 2013 14:28:58 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Mon, 8 Apr 2013 14:28:40 +0100 Message-Id: <1365427720-10926-1-git-send-email-chris@chris-wilson.co.uk> X-Mailer: git-send-email 1.7.10.4 X-Originating-IP: 78.156.73.22 Cc: Ben Widawsky Subject: [Intel-gfx] [PATCH] drm/i915: Use MLC (l3$) for context objects X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Enabling context support increases SwapBuffers latency by about 20% (measured on an i7-3720qm). We can offset that loss slightly by enabling faster caching for the contexts. As they are not backed by any particular cache (such as the sampler or render caches) our only option is to select the generic mid-level cache. This reduces the latency of the swap by about 5%. Oddly this effect can be observed running smokin-guns on IVB at 1280x1024: Using BLT copies for swaps: 151.67 fps Using Render copies for swaps (unpatched): 141.70 fps With contexts disabled: 150.23 fps With contexts in L3$: 150.77 fps Signed-off-by: Chris Wilson Cc: Ben Widawsky Cc: Kenneth Graunke Reviewed-by: Kenneth Graunke --- drivers/gpu/drm/i915/i915_gem_context.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index 94d873a..a1e8ecb 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -152,6 +152,13 @@ create_hw_context(struct drm_device *dev, return ERR_PTR(-ENOMEM); } + if (INTEL_INFO(dev)->gen >= 7) { + ret = i915_gem_object_set_cache_level(ctx->obj, + I915_CACHE_LLC_MLC); + if (ret) + goto err_out; + } + /* The ring associated with the context object is handled by the normal * object tracking code. We give an initial ring value simple to pass an * assertion in the context switch code.