When stealing pieces, only steal from slower peers

This commit is contained in:
Igor Katson 2023-12-25 09:08:16 -05:00
parent 1e525eb91e
commit 5d4ffae6de
No known key found for this signature in database
GPG key ID: B4EC22B66D61A3F5
2 changed files with 13 additions and 30 deletions

View file

@ -1030,18 +1030,15 @@ impl PeerHandler {
.map(|r| r.flatten())
}
/// Try to steal a piece from a slower peer. Threshold is
/// "how many times is my average download speed faster to be able to steal".
///
/// If this returns, an existing in-flight piece was marked to be ours.
fn try_steal_old_slow_piece(&self, threshold: f64) -> Option<ValidPieceIndex> {
let total = self
.state
.stats
.downloaded_and_checked_pieces
.load(Ordering::Acquire);
// heuristic for not enough precision in average time
if total < 20 {
return None;
}
let avg_time = self.state.stats.average_piece_download_time()?;
let my_avg_time = match self.counters.average_piece_download_time() {
Some(t) => t,
None => return None,
};
let mut g = self.state.lock_write("try_steal_old_slow_piece");
let (idx, elapsed, piece_req) = g
@ -1053,10 +1050,10 @@ impl PeerHandler {
.max_by_key(|(_, e, _)| *e)?;
// heuristic for "too slow peer"
if elapsed.as_secs_f64() > avg_time.as_secs_f64() * threshold {
if elapsed.as_secs_f64() > my_avg_time.as_secs_f64() * threshold {
debug!(
"will steal piece {} from {}: elapsed time {:?}, avg piece time: {:?}",
idx, piece_req.peer, elapsed, avg_time
"will steal piece {} from {}: elapsed time {:?}, my avg piece time: {:?}",
idx, piece_req.peer, elapsed, my_avg_time
);
piece_req.peer = self.addr;
piece_req.started = Instant::now();
@ -1469,7 +1466,7 @@ impl PeerHandler {
.fetch_add(piece_len, Ordering::Relaxed);
self.state.stats.total_piece_download_ms.fetch_add(
full_piece_download_time.as_millis() as u64,
Ordering::Release,
Ordering::Relaxed,
);
// Per-peer piece counters.

View file

@ -1,7 +1,4 @@
use std::{
sync::atomic::{AtomicU64, Ordering},
time::Duration,
};
use std::sync::atomic::AtomicU64;
#[derive(Default, Debug)]
pub struct AtomicStats {
@ -12,14 +9,3 @@ pub struct AtomicStats {
pub fetched_bytes: AtomicU64,
pub total_piece_download_ms: AtomicU64,
}
impl AtomicStats {
pub fn average_piece_download_time(&self) -> Option<Duration> {
let d = self.downloaded_and_checked_pieces.load(Ordering::Acquire);
let t = self.total_piece_download_ms.load(Ordering::Acquire);
if d == 0 {
return None;
}
Some(Duration::from_secs_f64(t as f64 / d as f64 / 1000f64))
}
}