[DX12] Multiple threads submitting and then waiting can cause 60sec hang #8267
Description
Description
On the DX12 backend, if two (or more, but never just one) threads submit work and then wait on that submitted work one of the threads will hang for almost exactly 60 seconds (plus or minus a millisecond or so) on fence.wait (at Threading::WaitForSingleObject. This read-locks the fence causing the other thread to get stuck in queue submit on the other thread because that tries to write-lock the fence. None of this happens on vulkan.
Repro steps
https://github.com/Vecvec/wgpu_dx12_timeout reproduces this. There seems to need to be a workload, but that is probably because otherwise the submit would have finished by the time the fence waits.
Expected vs observed behavior
like vulkan, there should be no 60 second hangs
Extra materials
start of the logs from running the program.
Compiling wgpu_dx12_timeout v0.1.0 (C:\Users\danie\code_projects\wgpu_dx12_timeout)
Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.85s
Running `target\debug\wgpu_dx12_timeout.exe`
selected device Intel(R) Arc(TM) Graphics in backend Dx12, features: Features { features_wgpu: FeaturesWGPU(TEXTURE_FORMAT_16BIT_NORM | TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES | TIMESTAMP_QUERY_INSIDE_ENCODERS | TIMESTAMP_QUERY_INSIDE_PASSES | MAPPABLE_PRIMARY_BUFFERS | TEXTURE_BINDING_ARRAY | STORAGE_RESOURCE_BINDING_ARRAY | SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING | STORAGE_TEXTURE_ARRAY_NON_UNIFORM_INDEXING | PARTIALLY_BOUND_BINDING_ARRAY | MULTI_DRAW_INDIRECT | MULTI_DRAW_INDIRECT_COUNT | PUSH_CONSTANTS | ADDRESS_MODE_CLAMP_TO_ZERO | ADDRESS_MODE_CLAMP_TO_BORDER | POLYGON_MODE_LINE | CONSERVATIVE_RASTERIZATION | VERTEX_WRITABLE_STORAGE | CLEAR_TEXTURE | TEXTURE_ATOMIC | TEXTURE_FORMAT_NV12 | EXPERIMENTAL_RAY_TRACING_ACCELERATION_STRUCTURE | EXPERIMENTAL_RAY_QUERY | SHADER_PRIMITIVE_INDEX | SHADER_INT64 | SUBGROUP | TEXTURE_INT64_ATOMIC | EXTENDED_ACCELERATION_STRUCTURE_VERTEX_FORMATS), features_webgpu: FeaturesWebGPU(DEPTH_CLIP_CONTROL | DEPTH32FLOAT_STENCIL8 | TEXTURE_COMPRESSION_BC | TEXTURE_COMPRESSION_BC_SLICED_3D | TIMESTAMP_QUERY | INDIRECT_FIRST_INSTANCE | SHADER_F16 | RG11B10UFLOAT_RENDERABLE | BGRA8UNORM_STORAGE | FLOAT32_FILTERABLE | DUAL_SOURCE_BLENDING) }
0
0
suspiciously long time - took 60.000504s to get to end of loop
suspiciously long time - took 59.999744s to get to end of submission
suspiciously long time - took 60.001125s to get to end of loop
100
100
suspiciously long time - took 60.007477s to get to end of loop
suspiciously long time - took 60.004585s to get to end of submission
suspiciously long time - took 60.00586s to get to end of loop
200
200
suspiciously long time - took 60.00143s to get to end of loop
suspiciously long time - took 59.99961s to get to end of submission
suspiciously long time - took 60.00068s to get to end of loop
300
300
400
400
500
500
600
600Platform
Both on wgpu 26.0.1 (latest version), and a fork of trunk. Happens on both my intel IGPU as well as my RTX 3050.