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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 507B8C433EF for ; Wed, 27 Oct 2021 08:27:50 +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 BA1AF61073 for ; Wed, 27 Oct 2021 08:27:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org BA1AF61073 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 27B4B6E4AD; Wed, 27 Oct 2021 08:27:49 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 50AF76E4AD for ; Wed, 27 Oct 2021 08:27:48 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10149"; a="253656470" X-IronPort-AV: E=Sophos;i="5.87,186,1631602800"; d="scan'208";a="253656470" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Oct 2021 01:27:24 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.87,186,1631602800"; d="scan'208";a="486566394" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by orsmga007.jf.intel.com with SMTP; 27 Oct 2021 01:27:21 -0700 Received: by stinkbox (sSMTP sendmail emulation); Wed, 27 Oct 2021 11:27:20 +0300 Date: Wed, 27 Oct 2021 11:27:20 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: "Kasireddy, Vivek" Cc: "intel-gfx@lists.freedesktop.org" , Maarten Lankhorst , Tvrtko Ursulin , "Navare, Manasi D" Message-ID: References: <20211026063811.1375040-1-vivek.kasireddy@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH] drm/i915/gem: Don't try to map and fence 8K/bigjoiner scanout buffers 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 Wed, Oct 27, 2021 at 06:41:25AM +0000, Kasireddy, Vivek wrote: > Hi Ville, > > > > > On Mon, Oct 25, 2021 at 11:38:11PM -0700, Vivek Kasireddy wrote: > > > On platforms capable of allowing 8K (7680 x 4320) modes, pinning 2 or > > > more framebuffers/scanout buffers results in only one that is mappable/ > > > fenceable. Therefore, pageflipping between these 2 FBs where only one > > > is mappable/fenceable creates latencies large enough to miss alternate > > > vblanks thereby producing less optimal framerate. > > > > > > This mainly happens because when i915_gem_object_pin_to_display_plane() > > > is called to pin one of the FB objs, the associated vma is identified > > > as misplaced and therefore i915_vma_unbind() is called which unbinds and > > > evicts it. This misplaced vma gets subseqently pinned only when > > > i915_gem_object_ggtt_pin_ww() is called without the mappable flag. This > > > results in a latency of ~10ms and happens every other vblank/repaint cycle. > > > > > > Testcase: > > > Running Weston and weston-simple-egl on an Alderlake_S (ADLS) platform > > > with a 8K@60 mode results in only ~40 FPS. Since upstream Weston submits > > > a frame ~7ms before the next vblank, the latencies seen between atomic > > > commit and flip event is 7, 24 (7 + 16.66), 7, 24..... suggesting that > > > it misses the vblank every other frame. > > > > > > Here is the ftrace snippet that shows the source of the ~10ms latency: > > > i915_gem_object_pin_to_display_plane() { > > > 0.102 us | i915_gem_object_set_cache_level(); > > > i915_gem_object_ggtt_pin_ww() { > > > 0.390 us | i915_vma_instance(); > > > 0.178 us | i915_vma_misplaced(); > > > i915_vma_unbind() { > > > __i915_active_wait() { > > > 0.082 us | i915_active_acquire_if_busy(); > > > 0.475 us | } > > > intel_runtime_pm_get() { > > > 0.087 us | intel_runtime_pm_acquire(); > > > 0.259 us | } > > > __i915_active_wait() { > > > 0.085 us | i915_active_acquire_if_busy(); > > > 0.240 us | } > > > __i915_vma_evict() { > > > ggtt_unbind_vma() { > > > gen8_ggtt_clear_range() { > > > 10507.255 us | } > > > 10507.689 us | } > > > 10508.516 us | } > > > > > > Cc: Maarten Lankhorst > > > Cc: Tvrtko Ursulin > > > Cc: Manasi Navare > > > Signed-off-by: Vivek Kasireddy > > > --- > > > drivers/gpu/drm/i915/display/intel_fb_pin.c | 11 +++++++++-- > > > drivers/gpu/drm/i915/display/intel_overlay.c | 11 ++++++++--- > > > drivers/gpu/drm/i915/gem/i915_gem_domain.c | 6 ++++-- > > > drivers/gpu/drm/i915/gem/i915_gem_object.h | 3 ++- > > > 4 files changed, 23 insertions(+), 8 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c > > b/drivers/gpu/drm/i915/display/intel_fb_pin.c > > > index 3f77f3013584..53c156d9a9f9 100644 > > > --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c > > > +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c > > > @@ -144,7 +144,7 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb, > > > > > > if (!ret) { > > > vma = i915_gem_object_pin_to_display_plane(obj, &ww, alignment, > > > - view, pinctl); > > > + view, pinctl, uses_fence); > > > if (IS_ERR(vma)) { > > > ret = PTR_ERR(vma); > > > goto err_unpin; > > > @@ -218,9 +218,16 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state) > > > INTEL_INFO(dev_priv)->display.cursor_needs_physical; > > > > > > if (!intel_fb_uses_dpt(fb)) { > > > + struct intel_crtc *crtc = to_intel_crtc(plane_state->hw.crtc); > > > + struct intel_crtc_state *crtc_state = > > > + to_intel_crtc_state(crtc->base.state); > > > + bool uses_fence = intel_plane_uses_fence(plane_state); > > > + bool is_bigjoiner = crtc_state->bigjoiner || > > > + crtc_state->bigjoiner_slave; > > > > Bigjoiner is just an implementation detail. It is not the cause of any > > of this. > [Kasireddy, Vivek] Right, bigjoiner/8K is just exposing the underlying issue; which is > that sometimes, large objects/scanout buffers that fail range overflow checks and thus > are not mappable/fenceable keep getting evicted and reinserted leading to latencies. > I guess I could mark an object/vma as permanently un-mappable/un-fenceable and try > not to map it subsequently but this would result in one scanout buffer that is mappable > but others that are not. Would this be acceptable -- assuming we are pageflipping > between multiple FBs? > Any ideas on solving this issue cleanly? We might just consider skipping PIN_MAPPABLE if the vma is too big. What the specific defition of "too big" would be I'm not sure. -- Ville Syrjälä Intel