I've been running with gfx.webrender.all enabled on Windows 10 for a couple weeks without any major stability problems, but this morning Firefox (content and chrome) started hanging intermittently. I think this problem started with Nightly 61.0a1 buildID 20180403100105 or maybe the day before. I can unblock Firefox by switching to a different application (or switching to another tab will sometimes work). The Windows Task Manager does not show any processes with suspiciously high CPU usage, so this feels more like a painting or event processing issue than the browser being unresponsive because it is too busy. I don't have good STR, but scrolling around in a large Google spreadsheet and dragging the page scrollbar will often reproduce the problem.

FWIW, I've hit this WebRender hang four times while filing this bug report. Here is my about:support information: Application Basics ------------------ Name: Firefox Version: 61.0a1 Build ID: 20180403220040 Update Channel: nightly User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0 OS: Windows_NT 10.0 Multiprocess Windows: 2/2 (Enabled by user) Web Content Processes: 8/7 Enterprise Policies: Inactive Google Key: Found Mozilla Location Service Key: Found Safe Mode: false Graphics -------- Features Compositing: WebRender Asynchronous Pan/Zoom: wheel input enabled; touch input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled WebGL 1 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 000000000000ecd8) EGL_VERSION: 1.4 (ANGLE 2.1.0.27cef491162b) 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 EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization 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 (Intel(R) HD Graphics 530 Direct3D11 vs_5_0 ps_5_0) WebGL 1 Driver Version: OpenGL ES 2.0 (ANGLE 2.1.0.27cef491162b) WebGL 1 Driver Extensions: GL_ANGLE_client_arrays 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_program_cache_control 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_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba 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_compression_s3tc_srgb 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_surfaceless_context 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_compressed_texture_s3tc_srgb 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: 000000000000ecd8) EGL_VERSION: 1.4 (ANGLE 2.1.0.27cef491162b) 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 EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization 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 (Intel(R) HD Graphics 530 Direct3D11 vs_5_0 ps_5_0) WebGL 2 Driver Version: OpenGL ES 3.0 (ANGLE 2.1.0.27cef491162b) WebGL 2 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_multiview GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control 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_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba 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_compression_s3tc_srgb 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_surfaceless_context 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_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context Direct2D: true Off Main Thread Painting Enabled: true DirectWrite: true (10.0.17127.1) GPU #1 Active: Yes Description: Intel(R) HD Graphics 530 Vendor ID: 0x8086 Device ID: 0x191b Driver Version: 23.20.16.4973 Driver Date: 2-28-2018 Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32 Subsys ID: 674e1a58 RAM: Unknown GPU #2 Active: No Description: NVIDIA GeForce GTX 970M Vendor ID: 0x10de Device ID: 0x13d8 Driver Version: 23.21.13.8873 Driver Date: 12-18-2017 Drivers: C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumdx.dll C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvrz.inf_amd64_7550cbd75f58b6c2\nvldumd.dll Subsys ID: 674e1a58 RAM: 6144 Diagnostics ClearType Parameters: Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 50 AzureCanvasAccelerated: 0 AzureCanvasBackend: direct2d 1.1 AzureCanvasBackend (UI Process): skia AzureContentBackend: skia AzureContentBackend (UI Process): skia AzureFallbackCanvasBackend (UI Process): cairo GPUProcessPid: 8968 GPUProcess: Terminate GPU Process Device Reset: Trigger Device Reset ClearType Parameters: Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 50 Decision Log WEBRENDER: opt-in by default: WebRender is an opt-in feature available by user: Enabled by pref

If you'd like me to bisect this bug with mozregression, just let me know.

Can you describe what you mean by "hanging"? Is this the same as bug 1447193?

(In reply to Kartikaya Gupta (email:kats@mozilla.com) from comment #3) > Can you describe what you mean by "hanging"? Is this the same as bug 1447193? I think this is different from bug 1447193. In that bug, portions of the page are not painted and clicking the page will cause the missing area to be painted. With the "hang" I see, the entire window (content and chrome) stops responding. The page is fully painted but I can't interact with it. I can't drag the scrollbar or click focus to other tabs in the same window. I can Alt+Tab focus to other Firefox windows of the same browser session, which will "unhang" the original window.

Ok, thanks. In that case getting a regression window would be useful.

Sotaro, I bisected is a regression to DirectComposition bug 1191971. If I set gfx.webrender.all = true and gfx.webrender.dcomp-win.enabled = true, I can reproduce the hang. If I set gfx.webrender.all = true and gfx.webrender.dcomp-win.enabled = false, I can't reproduce the hang. STR: 1. Load this bug page. 2. I scroll up and down the page using my laptop's trackpad. RESULT: After two or three trackpad flings, the window will stop responding.

I tested with several Win10 PCs, but I could not reproduce the problem. It might be caused by a driver problem. :cpeterson, can you reproduce the problem with another Win 10 PC that have different GPU?

(In reply to Sotaro Ikeda [:sotaro] from comment #7) > :cpeterson, can you reproduce the problem with another Win 10 PC that have > different GPU? I only have access to one Windows machine, but I can use the Nvidia Control Panel app to force my laptop to use either the Nvidia external GPU or the Intel integrated GPU. I can reproduce the hang with both the Nvidia and Intel GPU, though the hang feels like it is more difficult to reproduce on Intel GPU.

Happens to :abovens in trello.

Andreas, can you still reproduce this WebRender hang in Trello? I tried to reproduce this hang today after a couple weeks of not using WebRender, but I can no longer reproduce it. I used to be able to reliably reproduce it in less than a minute.

No, I can no longer reproduce it.

Thanks!