Vulkano: assertion failed: chunk.num_gpu_accesses >= 1 when drawing large number of meshes

[franckv]

I'm drawing a scene with a moderatly large number of meshes (~500).
Each mesh has its own transformation matrix that i need to upload in a uniform.
To do this, I instanciate a new FixedSizedDescriptor for each mesh and attach a CpuBufferPool containing the matrix data as follows:

         let command_buffer = {
             let mut builder =
                 AutoCommandBufferBuilder::primary_one_time_submit(device.clone(), queue.family()).unwrap()
                 .begin_render_pass(framebuffers[idx].clone(), false, vec![[0., 0., 1., 1.].into()]).unwrap();

             let mut descriptor_sets_pool = FixedSizeDescriptorSetsPool::new(pipeline.clone(), 0);

             for mesh in &meshes {
                 let uniforms_data = vs::ty::Data {
                     transform: mesh.transform.into(),
                 };

                 let uniforms = uniforms_buffer.next(uniforms_data).unwrap();

                 let set = Arc::new(descriptor_sets_pool.next().add_buffer(uniforms).unwrap().build().unwrap());

                 builder = builder.draw_indexed(pipeline.clone(), dynamic_state.clone(),
                 mesh.vbuf.clone(), mesh.ibuf.clone(), set.clone(), ()).unwrap();
             }

             builder.end_render_pass().unwrap().build().unwrap()
         };

         let future = last_frame.join(acquire_future)
             .then_execute(queue.clone(), command_buffer).unwrap()
             .then_swapchain_present(queue.clone(), swapchain.clone(), idx)
             .then_signal_fence_and_flush().unwrap();

This code double panicks on my setup (Linux / Intel(R) HD Graphics 620 (Kaby Lake GT2)) if the number of meshes is greater than 400 (it works fine for lower values):

thread 'test::tests::run' panicked at 'assertion failed: chunk.num_gpu_accesses >= 1', /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/buffer/cpu_pool.rs:659:8
note: Run with `RUST_BACKTRACE=1` for a backtrace.
thread 'test::tests::run' panicked at 'called `Result::unwrap()` on an `Err` value: "PoisonError { inner: .. }"', src/libcore/result.rs:906:4
stack backtrace:
   0:     0x555a2d5f5cfb - std::sys::imp::backtrace::tracing::imp::unwind_backtrace::h568550e9c3581ddc
   1:     0x555a2d5e3bb4 - std::sys_common::backtrace::print::hd8ec6866e3bd8b96
   2:     0x555a2d5fa5c9 - std::panicking::default_hook::{{closure}}::h92bf5ffea3e5961d
   3:     0x555a2d5fa274 - std::panicking::default_hook::h77acee2dd9d286bf
   4:     0x555a2d5faa7b - std::panicking::rust_panic_with_hook::hf6217f2eaf058be5
   5:     0x555a2d5fa904 - std::panicking::begin_panic::h1d02da2b82a54ae9
   6:     0x555a2d5fa875 - std::panicking::begin_panic_fmt::ha745e93a6afd4c9d
   7:     0x555a2d5fa80a - rust_begin_unwind
   8:     0x555a2d63c790 - core::panicking::panic_fmt::h664ef1a8778c7464
   9:     0x555a2d205093 - core::result::unwrap_failed::hb831264b7884902f
                               at /build/rust/src/rustc-1.22.1-src/src/libcore/macros.rs:23
  10:     0x555a2d1fe2ab - <core::result::Result<T, E>>::unwrap::hd3a6fd6e3b6e560d
                               at /build/rust/src/rustc-1.22.1-src/src/libcore/result.rs:772
  11:     0x555a2d29ab9c - <vulkano::buffer::cpu_pool::CpuBufferPoolChunk<T, A> as vulkano::buffer::traits::BufferAccess>::unlock::h65718f8b38ad0a51
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/buffer/cpu_pool.rs:672
  12:     0x555a2d29aefc - <vulkano::buffer::cpu_pool::CpuBufferPoolSubbuffer<T, A> as vulkano::buffer::traits::BufferAccess>::unlock::h066c19ec908e3f4f
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/buffer/cpu_pool.rs:770
  13:     0x555a2d20cd81 - <vulkano::command_buffer::synced::base::SyncCommandBuffer<P>>::unlock::hbbe20fffaac49292
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/command_buffer/synced/base.rs:1197
  14:     0x555a2d31040c - <vulkano::command_buffer::auto::AutoCommandBuffer<P> as vulkano::command_buffer::traits::CommandBuffer>::unlock::hccf43612ea4c919f
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/command_buffer/auto.rs:1332
  15:     0x555a2d1f4f2c - <vulkano::command_buffer::traits::CommandBufferExecFuture<F, Cb> as vulkano::sync::future::GpuFuture>::signal_finished::ha84d4ae9845ad65c
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/command_buffer/traits.rs:266
  16:     0x555a2d1f09a8 - <vulkano::swapchain::swapchain::PresentFuture<P> as vulkano::sync::future::GpuFuture>::signal_finished::h34d6954818f01b3b
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/swapchain/swapchain.rs:1065
  17:     0x555a2d1f07a7 - <vulkano::sync::future::fence_signal::FenceSignalFuture<F> as core::ops::drop::Drop>::drop::h620d0a00950dbfda
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/sync/future/fence_signal.rs:439
  18:     0x555a2d23ae64 - core::ptr::drop_in_place::hbc6f042bbfd9011d
                               at /build/rust/src/rustc-1.22.1-src/src/libcore/ptr.rs:59
  19:     0x555a2d231fa6 - core::ptr::drop_in_place::h2d73722a81190ff8
                               at /build/rust/src/rustc-1.22.1-src/src/libcore/ptr.rs:59
  20:     0x555a2d2390b4 - core::ptr::drop_in_place::h9e689a09ab63e8d9
                               at /build/rust/src/rustc-1.22.1-src/src/libcore/ptr.rs:59
  21:     0x555a2d3297ba - vulkano::command_buffer::traits::CommandBuffer::execute_after::h90fa8af39973cf22
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/command_buffer/traits.rs:137
  22:     0x555a2d32b037 - vulkano::sync::future::GpuFuture::then_execute::h08b4e2c3bda4567c
                               at /home/franck/.cargo/registry/src/github.com-1ecc6299db9ec823/vulkano-0.7.2/src/sync/future/mod.rs:158
  23:     0x555a2d332af3 - test_render::test::main::h34fb08f0fa4232e8
                               at src/test.rs:251
  24:     0x555a2d22f318 - test_render::test::tests::run::h805083d89b41f4f0
                               at src/test.rs:272
  25:     0x555a2d4f16d1 - <F as test::FnBox<T>>::call_box::h86ada89b85c2e3dc
  26:     0x555a2d4ffc67 - std::panicking::try::do_call::heeed6ba046a7fd0e
  27:     0x555a2d600767 - __rust_maybe_catch_panic
  28:     0x555a2d4ffbba - std::panicking::try::hca400f7f8efb03fe
  29:     0x555a2d5061aa - std::sys_common::backtrace::__rust_begin_short_backtrace::h8ca7496d05f742c7
  30:     0x555a2d5056c2 - <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once::h6fecce067f94cb9d
  31:     0x555a2d4ffc42 - std::panicking::try::do_call::h497a57d742c488d0
  32:     0x555a2d600767 - __rust_maybe_catch_panic
  33:     0x555a2d4ffb3b - std::panicking::try::h18d0fb22b272b72f
  34:     0x555a2d50a652 - <F as alloc::boxed::FnBox<A>>::call_box::h4867ea053e4e5548
  35:     0x555a2d5e6ee2 - std::sys::imp::thread::Thread::new::thread_start::h346554e78296580f
  36:     0x7f0b5b598089 - start_thread
  37:     0x7f0b5b0b842e - __clone
  38:                0x0 - <unknown>
thread panicked while panicking. aborting.
error: An unknown error occurred

Am I hitting a hardware limit here or am I doing something wrong ?

Thanks,

[lilith645]

I have encountered the same panick drawing simple 2D Textured Quads with unique uniform variables, although error occurs after trying to drawing ~100 quads or more.

I don't seem to be reaching anywhere near the limits of my gpu (Linux - Nvidia GTX 950m), unless there is some descriptorset or uniform variable limit i'm unaware of.

The main difference from your example is that im using a PersistentDescriptorSet instead of a FixedSizedDescriptor.

The closest current active issue that I have found that could be relevant is issue #758, as it reports the same error message

I must note though, on my program it runs correctly for ~1 second until it recreates the swap chain from some automatic vulkan resize call then produces the panick.

The furthest i have tracked the error is that it occurs when the .then_signal_fence_and_flush() function is called.

Hope something here is of help. (Would like to solve this issue as well, is quite frustrating)

[lilith645]

I noticed that It does not occur if I compile and run my code as release simply with
Cargo run --release

Which if it is the case for others with same situation, it could suggest that there could be an issue with BufferAccess/BufferPoolChunk(or the drivers not playing well) when not compiled with full optimisations by the compiler.

@franckv Does compiling and running it as release solve the issue for you as well?

[franckv]

Yes, I confirm that the issue does not occurs when running the code in release mode.
I managed to issue up to 50k draw calls per frame without a crash.

[tomaka]

The reason why it works in release is because this assertion is a debug_assert!.
The fact that it works doesn't mean that what happens is correct however.

[rukai]

Could anyone who has encountered this issue please test on the latest version in git master.

[franckv]

Yes, it looks like it is working fine now. Thank you.