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Diffstat (limited to 'book')
| -rw-r--r-- | book/en/src/by-example/tips.md | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/book/en/src/by-example/tips.md b/book/en/src/by-example/tips.md index 07a5c0b..79b9d71 100644 --- a/book/en/src/by-example/tips.md +++ b/book/en/src/by-example/tips.md @@ -89,3 +89,27 @@ after the function, not the interrupt / exception. Example below: ``` console $ cargo run --example binds {{#include ../../../../ci/expected/binds.run}}``` + +## Indirection for faster message passing + +Message passing always involves copying the payload from the sender into a +static variable and then from the static variable into the receiver. Thus +sending a large buffer, like a `[u8; 128]`, as a message involves two expensive +`memcpy`s. To minimize the message passing overhead one can use indirection: +instead of sending the buffer by value, one can send an owning pointer into the +buffer. + +One can use a global allocator to achieve indirection (`alloc::Box`, +`alloc::Rc`, etc.), which requires using the nightly channel as of Rust v1.34.0, +or one can use a statically allocated memory pool like [`heapless::Pool`]. + +[`heapless::Pool`]: https://docs.rs/heapless/0.4.3/heapless/pool/index.html + +Here's an example where `heapless::Pool` is used to "box" buffers of 128 bytes. + +``` rust +{{#include ../../../../examples/pool.rs}} +``` +``` console +$ cargo run --example binds +{{#include ../../../../ci/expected/pool.run}}``` |
