( )⚙ D11659 rhg: do not try to open a nodemap for an inline index

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Differential D11659

rhg: do not try to open a nodemap for an inline index
ClosedPublic

Authored by aalekseyev on Oct 14 2021, 9:03 AM.

Details

Reviewers
pulkit
Group Reviewers
hg-reviewers
Commits
rHG5e77bdc29d56: rhg: do not try to open a nodemap for an inline index
Summary

This saves an [open] system call per file, which is a small saving, but
it showed up in the profile at large file counts (it accounted for 30ms
out of 400ms needed for catting 10000 files, on a ZFS filesystem on Linux,
so ~3us per syscall).

Diff Detail

Repository
rHG Mercurial
Branch
default
Lint
No Linters Available
Unit
No Unit Test Coverage

Event Timeline

aalekseyev created this revision.Oct 14 2021, 9:03 AM
pulkit accepted this revision.Oct 14 2021, 2:40 PM
This revision is now accepted and ready to land.Oct 14 2021, 2:40 PM
aalekseyev added a commit: rHG5e77bdc29d56: rhg: do not try to open a nodemap for an inline index.Oct 14 2021, 6:35 PM
Closed by commit rHG5e77bdc29d56: rhg: do not try to open a nodemap for an inline index (authored by aalekseyev). · Explain Why
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

Diff 30802

rust/hg-core/src/revlog/index.rs

bytes, bytes,
offsets: None, offsets: None,
}) })
} }
} }
/// Value of the inline flag. /// Value of the inline flag.
pub fn is_inline(&self) -> bool { pub fn is_inline(&self) -> bool {
is_inline(&self.bytes) self.offsets.is_some()
} }
/// Return a slice of bytes if `revlog` is inline. Panic if not. /// Return a slice of bytes if `revlog` is inline. Panic if not.
pub fn data(&self, start: usize, end: usize) -> &[u8] { pub fn data(&self, start: usize, end: usize) -> &[u8] {
if !self.is_inline() { if !self.is_inline() {
panic!("tried to access data in the index of a revlog that is not inline"); panic!("tried to access data in the index of a revlog that is not inline");
} }
&self.bytes[start..end] &self.bytes[start..end]

rust/hg-core/src/revlog/revlog.rs

if index.is_inline() { if index.is_inline() {
None None
} else { } else {
let data_path = data_path.unwrap_or(&default_data_path); let data_path = data_path.unwrap_or(&default_data_path);
let data_mmap = repo.store_vfs().mmap_open(data_path)?; let data_mmap = repo.store_vfs().mmap_open(data_path)?;
Some(Box::new(data_mmap)) Some(Box::new(data_mmap))
}; };
let nodemap = NodeMapDocket::read_from_file(repo, index_path)?.map( let nodemap = if index.is_inline() {
None
} else {
NodeMapDocket::read_from_file(repo, index_path)?.map(
|(docket, data)| { |(docket, data)| {
nodemap::NodeTree::load_bytes( nodemap::NodeTree::load_bytes(
Box::new(data), Box::new(data),
docket.data_length, docket.data_length,
) )
}, },
); )
};
Ok(Revlog { Ok(Revlog {
index, index,
data_bytes, data_bytes,
nodemap, nodemap,
}) })
} }