add additional context to wgpu resource threading docs

This commit is contained in:
Carter Anderson 2020-04-15 11:58:33 -07:00
parent 318b7dee1a
commit 07cf7897b1

View file

@ -30,13 +30,15 @@ pub struct WgpuBindGroupInfo {
/// pass.
///
/// The biggest implication of this design (other than the additional boilerplate here) is that beginning a render pass
/// blocks writes to these resources. This means that if the pass attempts to write any resource, a deadlock will occur. It also means
/// blocks writes to these resources. This means that if the pass attempts to write any resource, a deadlock will occur. WgpuResourceRefs
/// only has immutable references, so the only way to make a deadlock happen is to access WgpuResources directly in the pass. It also means
/// that other threads attempting to write resources will need to wait for pass encoding to finish. Almost all writes should occur before
/// passes start, so this hopefully won't be a problem.
///
/// It is worth comparing the performance of this to transactional / copy-based approach. This design lock based design guarantees
/// It is worth comparing the performance of this to transactional / copy-based approaches. This lock based design guarantees
/// consistency, doesn't perform redundant allocations, and only blocks when a write is occurring. A copy based approach would
/// never block, but would require more allocations / state-synchronization, which I expect will be more expensive.
/// never block, but would require more allocations / state-synchronization, which I expect will be more expensive. It would also be
/// "eventually consistent" instead of "strongly consistent".
///
/// Single threaded implementations don't need to worry about these lifetimes constraints at all. RenderPasses can use a RenderContext's
/// WgpuResources directly. RenderContext already has a lifetime greater than the RenderPass.