raft: reduce allocation #2391
raft: reduce allocation #2391
Conversation
src/raft/raft.rs
Outdated
| let mci = mis[self.quorum() - 1]; | ||
| let term = self.term; | ||
| self.raft_log.maybe_commit(mci, term) | ||
| let mci = if self.prs.len() <= 5 { |
There was a problem hiding this comment.
So the matched IDs can be put in a [0; 5] array. Generally we only have 3 or 5 replicas.
There was a problem hiding this comment.
How about smallvec[1] ?
There was a problem hiding this comment.
Why use it? I think the final code should look almost the same.
There was a problem hiding this comment.
I think we should add a benchmark case here.
There was a problem hiding this comment.
The code will hardly change, an additional benchmark case seems redundant. My benchmark shows that use array is about 50% quicker.
When len is 3:
test bench_commit_array ... bench: 13 ns/iter (+/- 0)
test bench_commit_vec ... bench: 28 ns/iter (+/- 0)
When len is 5:
test bench_commit_array ... bench: 20 ns/iter (+/- 0)
test bench_commit_vec ... bench: 35 ns/iter (+/- 0)
src/raft/raft.rs
Outdated
| mis[self.quorum() - 1] | ||
| } else { | ||
| let mut mis = Vec::with_capacity(self.prs.len()); | ||
| for p in self.prs.values() { |
There was a problem hiding this comment.
can we change vec to slice and unify the two similar codes?
| ..Default::default() | ||
| }; | ||
| if !raft.msgs.is_empty() { | ||
| mem::swap(&mut raft.msgs, &mut rd.messages); |
There was a problem hiding this comment.
It's very obvious that mem::swap does not copy the heap values however drain.collect will allocate a new buffer then copy all the content from original.
For a 100 length u64 vector:
test bench_drain_collect ... bench: 105 ns/iter (+/- 2)
test bench_swap ... bench: 2 ns/iter (+/- 0)
BusyJay
force-pushed
the
busyjay/reduce-allocation
branch
from
e0a6e6d to
23a6c39
Compare
|
/run-unit-test |
|
/run-integration-test |
No description provided.