diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/swarm/blob.rs | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/src/swarm/blob.rs b/src/swarm/blob.rs index 694fff0..11bf3dc 100644 --- a/src/swarm/blob.rs +++ b/src/swarm/blob.rs @@ -16,7 +16,8 @@ //! sends at a time. //! * Fetching: the manifest from the first peer that has it (closest first, and only //! from a peer asked; of content, only with the size its reference names), then the -//! chunks, a few in flight per peer from up to [`MAX_SOURCES`] peers. Every chunk is +//! chunks, a few in flight per peer at first, more as they come (up to +//! [`MAX_WINDOW`]), from up to [`MAX_SOURCES`] peers. Every chunk is //! checked against the manifest; a peer that sends a bad one is dropped, a chunk //! that doesn't arrive in time is asked of another peer. The caller checks the whole //! (for a change: its hash). @@ -41,8 +42,12 @@ use crate::transport::{BlobBody, BlobId, BlobMessage, DeltaSpec, ParsedMessage}; const MAX_SERVING: usize = 8; /// Peers a download fetches chunks from at once. const MAX_SOURCES: usize = 4; -/// Chunks in flight per peer. +/// Chunks in flight per peer at first, and after a chunk timed out (from 1). const WINDOW: usize = 4; +/// At most this many in flight per peer: each chunk delivered allows one more, so a +/// link with a long round trip isn't left idle (4 chunks of 64 KiB per 400 ms round +/// trip are about 640 KiB/s; 32 about 5 MiB/s). +const MAX_WINDOW: usize = 32; /// Largest blob a download of unknown size accepts (a change: an epoch's snapshot is as /// large as the document). Content has a known size, and only that is accepted. const MAX_SIZE: u64 = 4 << 30; @@ -321,7 +326,7 @@ async fn serve( }; return reply(state, peer, id, body).await; } - for index in chunks.into_iter().take(WINDOW * 2) { + for index in chunks.into_iter().take(MAX_WINDOW) { let start = index as usize * chunk_size as usize; if start >= prepared.bytes.len() { continue; @@ -546,8 +551,8 @@ pub(crate) async fn fetch( chunks[slot] = Some(data); done += 1; last_progress = Instant::now(); - // A peer that delivers gets its full window back. - source.window = WINDOW; + // A peer that delivers may have one more in flight. + source.window = (source.window + 1).min(MAX_WINDOW); } Ok(Some((from, BlobBody::Missing))) => { sources.retain(|source| source.peer != from); |