abdul124/nac3
1
0
Fork 0
forked from M-Labs/nac3
Code Pull Requests Activity

runtime/comms: Faster RPC alloc

Browse Source 
We do busy polling for some time before doing await, for small
allocations we could avoid the context switching and reduce the latency.
This commit is contained in:
pca006132 2020-09-03 12:24:23 +08:00
parent cdc8ad8aee
commit 5e4bf8bbf7
1 changed files with 33 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
src/runtime/src/comms.rs
View File

@ -17,7 +17,7 @@ use libboard_zynq::{
},
timer::GlobalTimer,
};
use libcortex_a9::{semaphore::Semaphore, mutex::Mutex};
use libcortex_a9::{semaphore::Semaphore, mutex::Mutex, sync_channel::{Sender, Receiver}};
use futures::{select_biased, future::FutureExt};
use libasync::{smoltcp::{Sockets, TcpStream}, task};
use libconfig::{Config, net_settings};
@ -124,6 +124,35 @@ async fn read_string(stream: &TcpStream, max_length: usize) -> Result<String> {
Ok(String::from_utf8(bytes).map_err(|err| Error::Utf8Error(err.utf8_error()))?)
}
const RETRY_LIMIT: usize = 100;
async fn fast_send(sender: &mut Sender<'_, kernel::Message>, content: kernel::Message) {
let mut content = content;
for _ in 0..RETRY_LIMIT {
match sender.try_send(content) {
Ok(()) => {
return
},
Err(v) => {
content = v;
}
}
}
sender.async_send(content).await;
}
async fn fast_recv(receiver: &mut Receiver<'_, kernel::Message>) -> kernel::Message {
for _ in 0..RETRY_LIMIT {
match receiver.try_recv() {
Ok(v) => {
return v;
},
Err(()) => ()
}
}
receiver.async_recv().await
}
async fn handle_run_kernel(stream: Option<&TcpStream>, control: &Rc<RefCell<kernel::Control>>) -> Result<()> {
control.borrow_mut().tx.async_send(kernel::Message::StartRequest).await;
loop {
@ -143,7 +172,7 @@ async fn handle_run_kernel(stream: Option<&TcpStream>, control: &Rc<RefCell<kern
match host_request {
Request::RPCReply => {
let tag = read_bytes(stream, 512).await?;
let slot = match control.borrow_mut().rx.async_recv().await {
let slot = match fast_recv(&mut control.borrow_mut().rx).await {
kernel::Message::RpcRecvRequest(slot) => slot,
other => panic!("expected root value slot from core1, not {:?}", other),
};
@ -156,8 +185,8 @@ async fn handle_run_kernel(stream: Option<&TcpStream>, control: &Rc<RefCell<kern
0 as *mut ()
} else {
let mut control = control.borrow_mut();
control.tx.async_send(kernel::Message::RpcRecvReply(Ok(size))).await;
match control.rx.async_recv().await {
fast_send(&mut control.tx, kernel::Message::RpcRecvReply(Ok(size))).await;
match fast_recv(&mut control.rx).await {
kernel::Message::RpcRecvRequest(slot) => slot,
other => panic!("expected nested value slot from kernel CPU, not {:?}", other),
}