# Objective

- After a series of optimizations making render and postupdate more
parallel, `write_batched_instance_buffers` was regularly one of the
largest spans with very low thread use, sitting at 4ms in 1 4ms frame.
This makes it an ideal target to improve throughput. Note this
screenshot doesn't include some visibility system optimizations:

<img width="650" height="718" alt="image"
src="https://github.com/user-attachments/assets/bbd6762b-5145-48f8-a427-5da3cb11a04a"
/>


## Solution

- Spawn tasks for writing buffers to the GPU. This is especially helpful
for `current_input_buffer` and `previous_input_buffer`, which take about
the same time and are the longest buffer writes - moving these to tasks
effectively halves the time spent in the system.

<img width="588" height="251" alt="image"
src="https://github.com/user-attachments/assets/0a086e7a-1d3c-4c17-9d66-eff94196943d"
/>

- In the 250k bevymark_3d stress test, this saves 1.7ms in the system,
and 2.8ms in frame time

frametime

<img width="620" height="376" alt="image"
src="https://github.com/user-attachments/assets/a4c106ac-7668-4f8a-970f-71cbb8be851c"
/>

system

<img width="1384" height="744" alt="image"
src="https://github.com/user-attachments/assets/5c42227d-8ee5-4b84-bc1a-c04768356255"
/>



## Testing

- `cargo rer bevymark_3d --features=debug,trace_tracy -- --benchmark
--waves 250 --per-wave 1000`

---------

Co-authored-by: Kevin Chen <[email protected]>