revlog: optimize _chunkraw when startrev==endrev
In many cases, _chunkraw() is called with startrev==endrev. When
this is true, we can avoid an extra index lookup and some other
minor operations.
On the mozilla-unified repo, `hg perfrevlogchunks -c` says this
has the following impact:
! read w/ reused fd
! wall 0.371846 comb 0.370000 user 0.350000 sys 0.020000 (best of 27)
! wall 0.337930 comb 0.330000 user 0.300000 sys 0.030000 (best of 30)
! read batch w/ reused fd
! wall 0.014952 comb 0.020000 user 0.000000 sys 0.020000 (best of 197)
! wall 0.014866 comb 0.010000 user 0.000000 sys 0.010000 (best of 196)
So, we've gone from ~25x slower than batch to ~22.5x slower.
At this point, there's probably not much else we can do except
implement an optimized function in the index itself, including in C.
# Copyright 2010-2011 Fog Creek Software
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''largefile store working over Mercurial's wire protocol'''
from __future__ import absolute_import
from . import (
lfutil,
remotestore,
)
class wirestore(remotestore.remotestore):
def __init__(self, ui, repo, remote):
cap = remote.capable('largefiles')
if not cap:
raise lfutil.storeprotonotcapable([])
storetypes = cap.split(',')
if 'serve' not in storetypes:
raise lfutil.storeprotonotcapable(storetypes)
self.remote = remote
super(wirestore, self).__init__(ui, repo, remote.url())
def _put(self, hash, fd):
return self.remote.putlfile(hash, fd)
def _get(self, hash):
return self.remote.getlfile(hash)
def _stat(self, hashes):
'''For each hash, return 0 if it is available, other values if not.
It is usually 2 if the largefile is missing, but might be 1 the server
has a corrupted copy.'''
batch = self.remote.iterbatch()
for hash in hashes:
batch.statlfile(hash)
batch.submit()
return dict(zip(hashes, batch.results()))