Module timestamp_queries

Sample demonstrating different kinds of gpu timestamp queries.

Timestamp queries are typically used to profile how long certain operations take on the GPU. wgpu has several ways of performing gpu timestamp queries:

• passing wgpu::RenderPassTimestampWrites/wgpu::ComputePassTimestampWrites during render/compute pass creation. This writes timestamps for the beginning and end of a given pass. (enabled with wgpu::Features::TIMESTAMP_QUERY)
• wgpu::CommandEncoder::write_timestamp writes a timestamp between any commands recorded on an encoder. (enabled with wgpu::Features::TIMESTAMP_QUERY_INSIDE_ENCODERS)
• wgpu::RenderPass/ComputePass::write_timestamp writes a timestamp within commands of a render pass. Note that some GPU architectures do not support this. (native only, enabled with wgpu::Features::TIMESTAMP_QUERY_INSIDE_PASSES)

Any timestamp is written to a wgpu::QuerySet which needs to be resolved to a buffer with wgpu::BufferUsages::QUERY_RESOLVE. Since this usage is incompatible with wgpu::BufferUsages::MAP_READ we need to copy the resolved timestamps to a separate buffer afterwards.

The period, i.e. the unit of time, of the timestamps in wgpu is undetermined and needs to be queried with wgpu::Queue::get_timestamp_period in order to get comparable results.

Structs

• Queries 🔒
• QueryResults 🔒

Functions

• compute_pass 🔒
• main
• render_pass 🔒
• run 🔒
• submit_render_and_compute_pass_with_queries 🔒