1405745 - 1+ second jank in LayerManagerMLGPU::EndTransaction scrolling amazon product page during load

Status: RESOLVED WONTFIX

(Core :: Graphics: Layers, defect, P2)

Description

[Ben Kelly [:bkelly, not reviewing]]

Please see this profile:

https://perfht.ml/2xgUyNZ

This was measured by:

1. Start collecting the profile.
2. Load this page:

https://www.amazon.com/How-cked-Your-Management-uncomfortable/dp/0995964300/ref=sr_1_1

3. Scroll down immediately while its loading content.

I originally saw this on FF57 beta, but this profile is from FF58.

Comment 1

[Ben Kelly [:bkelly, not reviewing]]

About support:

Application Basics
------------------

Name: Firefox
Version: 58.0a1
Build ID: 20171004100049
Update Channel: nightly
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
OS: Windows_NT 10.0
Multiprocess Windows: 1/1 (Enabled by default)
Web Content Processes: 4/4
Stylo: true (enabled by default)
Google Key: Found
Mozilla Location Service Key: Found
Safe Mode: false

Crash Reports for the Last 3 Days
---------------------------------

All Crash Reports

Nightly Features
----------------

Name: Activity Stream
Version: 2017.09.29.0895-52552f5e
ID: [e-mail]

Name: Application Update Service Helper
Version: 2.0
ID: [e-mail]

Name: Firefox Screenshots
Version: 19.1.0
ID: [e-mail]

Name: FlyWeb
Version: 1.0.0
ID: [e-mail]

Name: Follow-on Search Telemetry
Version: 0.9.3
ID: [e-mail]

Name: Form Autofill
Version: 1.0
ID: [e-mail]

Name: Multi-process staged rollout
Version: 3.05
ID: [e-mail]

Name: Photon onboarding
Version: 0.1
ID: [e-mail]

Name: Pocket
Version: 1.0.5
ID: [e-mail]

Name: Presentation
Version: 1.0.0
ID: [e-mail]

Name: Shield Recipe Client
Version: 76
ID: [e-mail]

Name: Web Compat
Version: 1.1
ID: [e-mail]

Name: WebCompat Reporter
Version: 1.0.0
ID: [e-mail]

Extensions
----------

Name: Gecko Profiler
Version: 0.17
Enabled: true
ID: [e-mail]

Graphics
--------

Features
Compositing: Direct3D 11 (Advanced Layers)
Asynchronous Pan/Zoom: wheel input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled
WebGL 1 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000010acb) EGL_VERSION: 1.4 (ANGLE 2.1.0.dec065540d5f) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture_nv12 EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses
WebGL 1 Driver Renderer: Google Inc. -- ANGLE (NVIDIA Quadro M2000 Direct3D11 vs_5_0 ps_5_0)
WebGL 1 Driver Version: OpenGL ES 2.0 (ANGLE 2.1.0.dec065540d5f)
WebGL 1 Driver Extensions: GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object
WebGL 1 Extensions: ANGLE_instanced_arrays EXT_blend_minmax EXT_color_buffer_half_float EXT_frag_depth EXT_sRGB EXT_shader_texture_lod EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_element_index_uint OES_standard_derivatives OES_texture_float OES_texture_float_linear OES_texture_half_float OES_texture_half_float_linear OES_vertex_array_object WEBGL_color_buffer_float WEBGL_compressed_texture_s3tc WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_depth_texture WEBGL_draw_buffers WEBGL_lose_context
WebGL 2 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000010acb) EGL_VERSION: 1.4 (ANGLE 2.1.0.dec065540d5f) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture_nv12 EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses
WebGL 2 Driver Renderer: Google Inc. -- ANGLE (NVIDIA Quadro M2000 Direct3D11 vs_5_0 ps_5_0)
WebGL 2 Driver Version: OpenGL ES 3.0 (ANGLE 2.1.0.dec065540d5f)
WebGL 2 Driver Extensions: GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_float GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_norm16 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_EGL_image_external_essl3 GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object
WebGL 2 Extensions: EXT_color_buffer_float EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_texture_float_linear WEBGL_compressed_texture_s3tc WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context
Direct2D: true
Off Main Thread Painting Enabled: true
DirectWrite: true (10.0.15063.483)
GPU #1
Active: Yes
Description: NVIDIA Quadro M2000
Vendor ID: 0x10de
Device ID: 0x1430
Driver Version: 23.21.13.8508
Driver Date: 7-25-2017
Drivers: C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumdx.dll C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nv_dispwi.inf_amd64_a89e65bee15af219\nvldumd.dll
Subsys ID: 119010de
RAM: 4096

Diagnostics
AzureCanvasAccelerated: 0
AzureCanvasBackend: Direct2D 1.1
AzureCanvasBackend (UI Process): skia
AzureContentBackend: Direct2D 1.1
AzureContentBackend (UI Process): skia
AzureFallbackCanvasBackend (UI Process): cairo
GPUProcessPid: 11036
GPUProcess: Terminate GPU Process
Device Reset: Trigger Device Reset
Decision Log
WEBRENDER:
opt-in by default: WebRender is an opt-in feature




Media
-----

Audio Backend: wasapi
Max Channels: 2
Preferred Channel Layout: stereo
Preferred Sample Rate: 48000
Output Devices
Name: Group
DELL U2410-0 (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Speakers (Logitech USB Headset): USB\VID_046D&PID_0A44&MI_00\7&22206c37&0&0000
DELL U2410-0 (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
NVIDIA HDMI Output (Port 0) (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
NVIDIA HDMI Output (Port 1) (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Speakers (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
DELL P2715Q-8 (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
NVIDIA Output (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
NVIDIA Output (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
DELL P2715Q-8 (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Input Devices
Name: Group
Center (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Internal AUX Jack (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Internal AUX Jack (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Microphone (HD Pro Webcam C920): USB\VID_046D&PID_082D&MI_02\6&37c025da&1&0002
Side (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Stereo Mix (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Microphone (Logitech USB Headset): USB\VID_046D&PID_0A44&MI_00\7&22206c37&0&0000
Microphone (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Internal AUX Jack (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Internal AUX Jack (NVIDIA High Definition Audio): HDAUDIO\FUNC_01&VEN_10DE&DEV_0072&SUBSYS_10DE1190&REV_1001\5&28edd795&0&0001
Line In (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Subwoofer (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Front (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Microphone (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001
Line In (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0662&SUBSYS_17AA1031&REV_1003\4&1c98c822&0&0001

Important Modified Preferences
------------------------------

accessibility.typeaheadfind.flashBar: 0
browser.cache.disk.capacity: 358400
browser.cache.disk.filesystem_reported: 1
browser.cache.disk.smart_size.first_run: false
browser.cache.frecency_experiment: 2
browser.places.smartBookmarksVersion: 8
browser.sessionstore.upgradeBackup.latestBuildID: 20171004100049
browser.startup.homepage_override.buildID: 20171004100049
browser.startup.homepage_override.mstone: 58.0a1
browser.urlbar.daysBeforeHidingSuggestionsPrompt: 0
browser.urlbar.lastSuggestionsPromptDate: 20170524
browser.urlbar.timesBeforeHidingSuggestionsHint: 0
browser.urlbar.usepreloadedtopurls.enabled: false
dom.fetchController.enabled: true
dom.fetchObserver.enabled: true
dom.forms.autocomplete.formautofill: true
dom.push.userAgentID: 8ab2b19d9bc74d31b4ea5184e352d9bb
dom.streams.enabled: true
extensions.lastAppVersion: 58.0a1
javascript.options.asyncstack: false
javascript.options.streams: true
layers.mlgpu.sanity-test-failed: false
media.gmp-gmpopenh264.abi: x86_64-msvc-x64
media.gmp-gmpopenh264.lastUpdate: 1490212978
media.gmp-gmpopenh264.version: 1.6
media.gmp-manager.buildID: 20170926100259
media.gmp-manager.lastCheck: 1506443025
media.gmp-widevinecdm.abi: x86_64-msvc-x64
media.gmp-widevinecdm.lastUpdate: 1504625635
media.gmp-widevinecdm.version: 1.4.8.1008
media.gmp.storage.version.observed: 1
media.hardware-video-decoding.failed: false
network.cookie.prefsMigrated: true
network.predictor.cleaned-up: true
places.database.lastMaintenance: 1506443064
places.history.expiration.transient_current_max_pages: 104858
plugin.disable_full_page_plugin_for_types: application/pdf
privacy.trackingprotection.introCount: 20
security.sandbox.content.tempDirSuffix: {5784d112-85c7-45d5-94d5-3be443f2634a}
services.sync.declinedEngines:
services.sync.engine.addresses.available: true
storage.vacuum.last.index: 1
storage.vacuum.last.places.sqlite: 1503944535
ui.osk.debug.keyboardDisplayReason: IKPOS: Touch screen not found.

Important Locked Preferences
----------------------------

Places Database
---------------

JavaScript
----------

Incremental GC: true

Accessibility
-------------

Activated: false
Prevent Accessibility: 0
Accessible Handler Used: true
Accessibility Instantiator:

Library Versions
----------------

NSPR
Expected minimum version: 4.17
Version in use: 4.17

NSS
Expected minimum version: 3.33
Version in use: 3.33

NSSSMIME
Expected minimum version: 3.33
Version in use: 3.33

NSSSSL
Expected minimum version: 3.33
Version in use: 3.33

NSSUTIL
Expected minimum version: 3.33
Version in use: 3.33

Experimental Features
---------------------

Name: Unaccelerated Compositor Process Nightly 56
ID: [e-mail]
Description: Measures the impact of enabling compositor process for users without hardware acceleration in Firefox Nightly 56 on Windows
Active: false
End Date: 1501250559228
Homepage:
Branch: disqualified

Name: Flash as Click-To-Activate
ID: [e-mail]
Description: Measuring the impact of setting Flash as Click-To-Activate by default
Active: false
End Date: 1493646448287
Homepage:
Branch: test-waiting

Sandbox
-------

Content Process Sandbox Level: 4
Effective Content Process Sandbox Level: 4

Comment 2

[Bas Schouten (:bas.schouten)]

Could you post a profile that includes the paint thread? You can do this by going into the profiler settings and adding ',PaintThread' to the threads.

Comment 3

[Ben Kelly [:bkelly, not reviewing]]

Sure:  https://perfht.ml/2fRk4XB

Comment 4

[Bas Schouten (:bas.schouten)]

(In reply to Ben Kelly [:bkelly] from comment #3)
> Sure:  https://perfht.ml/2fRk4XB

Interestingly enough, this profile displays a different issue than the first one (this one was somewhat expected in some situations and is already marked as blocking for OMTP riding the trains), any chance you could do another one or two, hopefully one of them will hit the issue your first profile hit, that one looks a little more scary to me.

Comment 5

[Ben Kelly [:bkelly, not reviewing]]

Does this one capture it?  https://perfht.ml/2wyLxA6

Comment 6

[Milan Sreckovic [:milan] (needinfo for best results)]

If this happened in 57, then it isn't OMTP, right?  Ben, do you get the same problem in 57 with advanced layers (layers.mlgpu.enabled) disabled?

Comment 7

[Ben Kelly [:bkelly, not reviewing]]

(In reply to Milan Sreckovic [:milan] from comment #6)
> If this happened in 57, then it isn't OMTP, right?  Ben, do you get the same
> problem in 57 with advanced layers (layers.mlgpu.enabled) disabled?

Setting this pref to false seems to reduce jank of the page in comment 0.  Setting the pref back to true seems to bring some jank back.  Its variable, though, so its hard to quantify.  I noticed more jank when the pref was set to true, though.

Comment 8

[Bas Schouten (:bas.schouten)]

(In reply to Ben Kelly [:bkelly] from comment #5)
> Does this one capture it?  https://perfht.ml/2wyLxA6

Umm... it seems to but then there seems to be hardly any samples? I wonder if something about profiling the paint thread is messed up.. Markus.. do you understand this?

Comment 9

[Bas Schouten (:bas.schouten)]

(In reply to Milan Sreckovic [:milan] from comment #6)
> If this happened in 57, then it isn't OMTP, right?  Ben, do you get the same
> problem in 57 with advanced layers (layers.mlgpu.enabled) disabled?

Based on the profiles, I'm willing to believe OMTP made this a little worse (although it may just have made some of the timings a little different making it a little more noticeable), we have reason to believe bug 1395478 & 1399692 will at least help this, which are both considered blocking OMTP riding the trains.

There's some vague data in the profiles at well though, which may or may not indicate a real problem, that may also have to be solved.

Comment 10

[Markus Stange [:mstange]]

(In reply to Bas Schouten (:bas.schouten) from comment #8)
> (In reply to Ben Kelly [:bkelly] from comment #5)
> > Does this one capture it?  https://perfht.ml/2wyLxA6
> 
> Umm... it seems to but then there seems to be hardly any samples?

This link includes a search filter. You can clear the search text field in order to see all the samples.

Comment 11

[Bas Schouten (:bas.schouten)]

So, it seems the time spent here on the content process main thread, is spent waiting for the front to back buffer painting to complete. This would be helped by bug 1399692. (Having said that, I don't see how OMTP could have made this worse, the profile indicates the painting thread is idle during this time, so there should be no contention)

The time spent in the compositor is just the compositor waiting for the GPU to finish the previous frame. This has been a known issue on some websites, although these numbers are particularly sad. Again it's not clear to me why OMTP would make this a little worse, but maybe because we're trying to draw more frames (i.e. 'feeding' the GPU more from the content process), or because there's some sort of contention on the GPU between the front to backbuffer copy and the paintthread that's not visible in the profile. If that is true we should see this improve with bug 1399692.

Comment 12

[David Anderson [:dvander] - inactive, e-mail if emergency]

If this happened on 57 we'd need a separate profile from that version to see what's going on. But Bas's comment sounds right - OMTP might exacerbate the problem but if we're getting GPU contention it would have always hurt the main thread.

Comment 13

[Marcia Knous [:marcia]]

Since this is fix optional for 57, we will not track it.