From patchwork Tue Jun 27 17:37:31 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 9812869 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1923160329 for ; Tue, 27 Jun 2017 17:37:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A667D286D7 for ; Tue, 27 Jun 2017 17:37:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 98FF7286F9; Tue, 27 Jun 2017 17:37:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2E7BB286D7 for ; Tue, 27 Jun 2017 17:37:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A50118915A; Tue, 27 Jun 2017 17:37:52 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8FFFD896C4 for ; Tue, 27 Jun 2017 17:37:50 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 7490711-1500050 for multiple; Tue, 27 Jun 2017 18:37:30 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Tue, 27 Jun 2017 18:37:31 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 27 Jun 2017 18:37:31 +0100 Message-Id: <20170627173731.11566-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.13.1 X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH] drm/i915: Drop flushing of the object free list/worker from i915_gem_suspend X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP i915_gem_suspend() is called from all of our finalization paths (suspend, hibernate, unload). i915_gem_drain_freed_objects() adds an arbitrary delay as it uses an rcu_barrier() to ensure that there are no more freed objects in flight, and this delay causes a large amount of variability in suspend timings. For S3 suspend, we do not need to free pages as doing so does not impact at all upon the system in its suspended state, unlike S4 hibernation where we do want the hibernation image to be as small as possible. Therefore we can forgo waiting inside i915_gem_suspend(), so long as we ensure that we do cleanup before unload (see i915_gem_load_cleanup()) and prefer to reap our objects prior to hibernation (see i915_gem_freeze()). Removing the rcu_barrier() from i915_gem_suspend() improves S3 latency by about 30ms on Skylake (ymmv). Reported-by: David Weinehall Signed-off-by: Chris Wilson Cc: David Weinehall Tested-by: David Weinehall Reviewed-by: David Weinehall --- drivers/gpu/drm/i915/i915_gem.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 36d838677982..f38c84e485ab 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -4597,8 +4597,6 @@ int i915_gem_suspend(struct drm_i915_private *dev_priv) while (flush_delayed_work(&dev_priv->gt.idle_work)) ; - i915_gem_drain_freed_objects(dev_priv); - /* Assert that we sucessfully flushed all the work and * reset the GPU back to its idle, low power state. */