# Objective
`extract_meshes` can easily be one of the most expensive operations in
the blocking extract schedule for 3D apps. It also has no fundamentally
serialized parts and can easily be run across multiple threads. Let's
speed it up by parallelizing it!
## Solution
Use the `ThreadLocal<Cell<Vec<T>>>` approach utilized by #7348 in
conjunction with `Query::par_iter` to build a set of thread-local
queues, and collect them after going wide.
## Performance
Using `cargo run --profile stress-test --features trace_tracy --example
many_cubes`. Yellow is this PR. Red is main.
`extract_meshes`:
An average reduction from 1.2ms to 770us is seen, a 41.6% improvement.
Note: this is still not including #9950's changes, so this may actually
result in even faster speedups once that's merged in.
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