dirstate-tree: Skip readdir() in `hg status -mard`
When running the status algorithm in a mode where we don’t list unknown
or ignored files, all we care about are files that are listed in the dirstate.
We can there for skip making expensive calls to readdir() to list the contents
of filesystem directories, and instead only run stat() to get the filesystem
state of files listed in the dirstate. (This state may be an error for files
that don’t exist anymore on the filesystem.)
On 16 CPU threads, this reduces the time spent in the `status()` function for
`hg status -mard` on an old snapshot of mozilla-central from ~70ms to ~50ms.
Differential Revision: https://phab.mercurial-scm.org/D10752
# dirstatenonnormalcheck.py - extension to check the consistency of the
# dirstate's non-normal map
#
# For most operations on dirstate, this extensions checks that the nonnormalset
# contains the right entries.
# It compares the nonnormal file to a nonnormalset built from the map of all
# the files in the dirstate to check that they contain the same files.
from __future__ import absolute_import
from mercurial import (
dirstate,
extensions,
)
def nonnormalentries(dmap):
"""Compute nonnormal entries from dirstate's dmap"""
res = set()
for f, e in dmap.iteritems():
if e[0] != b'n' or e[3] == -1:
res.add(f)
return res
def checkconsistency(ui, orig, dmap, _nonnormalset, label):
"""Compute nonnormalset from dmap, check that it matches _nonnormalset"""
nonnormalcomputedmap = nonnormalentries(dmap)
if _nonnormalset != nonnormalcomputedmap:
ui.develwarn(b"%s call to %s\n" % (label, orig), config=b'dirstate')
ui.develwarn(b"inconsistency in nonnormalset\n", config=b'dirstate')
ui.develwarn(b"[nonnormalset] %s\n" % _nonnormalset, config=b'dirstate')
ui.develwarn(b"[map] %s\n" % nonnormalcomputedmap, config=b'dirstate')
def _checkdirstate(orig, self, arg):
"""Check nonnormal set consistency before and after the call to orig"""
checkconsistency(
self._ui, orig, self._map, self._map.nonnormalset, b"before"
)
r = orig(self, arg)
checkconsistency(
self._ui, orig, self._map, self._map.nonnormalset, b"after"
)
return r
def extsetup(ui):
"""Wrap functions modifying dirstate to check nonnormalset consistency"""
dirstatecl = dirstate.dirstate
devel = ui.configbool(b'devel', b'all-warnings')
paranoid = ui.configbool(b'experimental', b'nonnormalparanoidcheck')
if devel:
extensions.wrapfunction(dirstatecl, '_writedirstate', _checkdirstate)
if paranoid:
# We don't do all these checks when paranoid is disable as it would
# make the extension run very slowly on large repos
extensions.wrapfunction(dirstatecl, 'normallookup', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'otherparent', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'normal', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'write', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'add', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'remove', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'merge', _checkdirstate)
extensions.wrapfunction(dirstatecl, 'drop', _checkdirstate)