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Differential D8513

rust-dirstatemap: don't read the dirstate when requesting parents
ClosedPublic

Authored by Alphare on May 11 2020, 11:05 AM.

Details

Reviewers
marmoute
Group Reviewers
hg-reviewers
Commits
rHG18e36ff8b414: rust-dirstatemap: don't read the dirstate when requesting parents
Summary

A future patch for issue 6303 reveals a big performance regression in the Rust
DirstateMap that reads the entire dirstate when requesting parents instead
of the first 40 bytes.

perfdiscovery gets a *significant* speedup (from 0.101 to 0.016) when applied
against said patch.
I'm assuming it has other performance benefits, but this is already a good
enough win.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

Alphare created this revision.May 11 2020, 11:05 AM
marmoute accepted this revision.May 13 2020, 11:30 AM
marmoute added a subscriber: marmoute.

This looks good to me.

Alphare edited the summary of this revision. (Show Details)May 14 2020, 4:29 PM
Alphare added a commit: rHG18e36ff8b414: rust-dirstatemap: don't read the dirstate when requesting parents.May 14 2020, 4:39 PM
This revision was not accepted when it landed; it landed in state Needs Review.
Closed by commit rHG18e36ff8b414: rust-dirstatemap: don't read the dirstate when requesting parents (authored by Alphare). · Explain Why
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/dirstate.py (18 lines)

Diff 21385

mercurial/dirstate.py

def nonnormalentries(self): def nonnormalentries(self):
return self._rustmap.nonnormalentries() return self._rustmap.nonnormalentries()
def get(self, *args, **kwargs): def get(self, *args, **kwargs):
return self._rustmap.get(*args, **kwargs) return self._rustmap.get(*args, **kwargs)
@propertycache @propertycache
def _rustmap(self): def _rustmap(self):
self._rustmap = rustmod.DirstateMap(self._root) """
Fills the Dirstatemap when called.
Use `self._inner_rustmap` if reading the dirstate is not necessary.
"""
self._rustmap = self._inner_rustmap
self.read() self.read()
return self._rustmap return self._rustmap
@propertycache
def _inner_rustmap(self):
"""
Does not fill the Dirstatemap when called. This allows for
optimizations where only setting/getting the parents is needed.
"""
self._inner_rustmap = rustmod.DirstateMap(self._root)
return self._inner_rustmap
@property @property
def copymap(self): def copymap(self):
return self._rustmap.copymap() return self._rustmap.copymap()
def preload(self): def preload(self):
self._rustmap self._rustmap
def clear(self): def clear(self):
self._rustmap.clear() self._rustmap.clear()
self._inner_rustmap.clear()
self.setparents(nullid, nullid) self.setparents(nullid, nullid)
util.clearcachedproperty(self, b"_dirs") util.clearcachedproperty(self, b"_dirs")
util.clearcachedproperty(self, b"_alldirs") util.clearcachedproperty(self, b"_alldirs")
util.clearcachedproperty(self, b"dirfoldmap") util.clearcachedproperty(self, b"dirfoldmap")
def items(self): def items(self):
return self._rustmap.items() return self._rustmap.items()
fp.close() fp.close()
except IOError as err: except IOError as err:
if err.errno != errno.ENOENT: if err.errno != errno.ENOENT:
raise raise
# File doesn't exist, so the current state is empty # File doesn't exist, so the current state is empty
st = b'' st = b''
try: try:
self._parents = self._rustmap.parents(st) self._parents = self._inner_rustmap.parents(st)
except ValueError: except ValueError:
raise error.Abort( raise error.Abort(
_(b'working directory state appears damaged!') _(b'working directory state appears damaged!')
) )
return self._parents return self._parents
def read(self): def read(self):