Mercurial > hg
view hgext/relink.py @ 23497:5817f71c2336
obsstore: disable garbage collection during initialization (issue4456)
Python garbage collection is triggered by container creation. So code that
creates a lot of tuples tends to trigger GC a lot. We disable the gc during
obsolescence marker parsing and associated initialization. This provides an
interesting speedup (25%).
Load marker function on my 58758 markers repo:
before: 0.468247 seconds
after: 0.344362 seconds
The benefit is a bit less visible overall. With python2.6 on my system I see:
after: 0.60
before: 0.53
The difference is probably explained by the delaying of a costly GC. (but there
is still a win). Marking involved tuples, lists and dicts as ignorable by the
garbage collector should give us more benefit. But this is another adventure.
Thanks goes to Siddharth Agarwal for the lead.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
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date | Wed, 26 Nov 2014 16:58:31 -0800 |
parents | da0eb4970913 |
children | 80c5b2666a96 |
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# Mercurial extension to provide 'hg relink' command # # Copyright (C) 2007 Brendan Cully <brendan@kublai.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """recreates hardlinks between repository clones""" from mercurial import cmdutil, hg, util from mercurial.i18n import _ import os, stat cmdtable = {} command = cmdutil.command(cmdtable) testedwith = 'internal' @command('relink', [], _('[ORIGIN]')) def relink(ui, repo, origin=None, **opts): """recreate hardlinks between two repositories When repositories are cloned locally, their data files will be hardlinked so that they only use the space of a single repository. Unfortunately, subsequent pulls into either repository will break hardlinks for any files touched by the new changesets, even if both repositories end up pulling the same changes. Similarly, passing --rev to "hg clone" will fail to use any hardlinks, falling back to a complete copy of the source repository. This command lets you recreate those hardlinks and reclaim that wasted space. This repository will be relinked to share space with ORIGIN, which must be on the same local disk. If ORIGIN is omitted, looks for "default-relink", then "default", in [paths]. Do not attempt any read operations on this repository while the command is running. (Both repositories will be locked against writes.) """ if (not util.safehasattr(util, 'samefile') or not util.safehasattr(util, 'samedevice')): raise util.Abort(_('hardlinks are not supported on this system')) src = hg.repository(repo.baseui, ui.expandpath(origin or 'default-relink', origin or 'default')) ui.status(_('relinking %s to %s\n') % (src.store.path, repo.store.path)) if repo.root == src.root: ui.status(_('there is nothing to relink\n')) return if not util.samedevice(src.store.path, repo.store.path): # No point in continuing raise util.Abort(_('source and destination are on different devices')) locallock = repo.lock() try: remotelock = src.lock() try: candidates = sorted(collect(src, ui)) targets = prune(candidates, src.store.path, repo.store.path, ui) do_relink(src.store.path, repo.store.path, targets, ui) finally: remotelock.release() finally: locallock.release() def collect(src, ui): seplen = len(os.path.sep) candidates = [] live = len(src['tip'].manifest()) # Your average repository has some files which were deleted before # the tip revision. We account for that by assuming that there are # 3 tracked files for every 2 live files as of the tip version of # the repository. # # mozilla-central as of 2010-06-10 had a ratio of just over 7:5. total = live * 3 // 2 src = src.store.path pos = 0 ui.status(_("tip has %d files, estimated total number of files: %s\n") % (live, total)) for dirpath, dirnames, filenames in os.walk(src): dirnames.sort() relpath = dirpath[len(src) + seplen:] for filename in sorted(filenames): if filename[-2:] not in ('.d', '.i'): continue st = os.stat(os.path.join(dirpath, filename)) if not stat.S_ISREG(st.st_mode): continue pos += 1 candidates.append((os.path.join(relpath, filename), st)) ui.progress(_('collecting'), pos, filename, _('files'), total) ui.progress(_('collecting'), None) ui.status(_('collected %d candidate storage files\n') % len(candidates)) return candidates def prune(candidates, src, dst, ui): def linkfilter(src, dst, st): try: ts = os.stat(dst) except OSError: # Destination doesn't have this file? return False if util.samefile(src, dst): return False if not util.samedevice(src, dst): # No point in continuing raise util.Abort( _('source and destination are on different devices')) if st.st_size != ts.st_size: return False return st targets = [] total = len(candidates) pos = 0 for fn, st in candidates: pos += 1 srcpath = os.path.join(src, fn) tgt = os.path.join(dst, fn) ts = linkfilter(srcpath, tgt, st) if not ts: ui.debug('not linkable: %s\n' % fn) continue targets.append((fn, ts.st_size)) ui.progress(_('pruning'), pos, fn, _('files'), total) ui.progress(_('pruning'), None) ui.status(_('pruned down to %d probably relinkable files\n') % len(targets)) return targets def do_relink(src, dst, files, ui): def relinkfile(src, dst): bak = dst + '.bak' os.rename(dst, bak) try: util.oslink(src, dst) except OSError: os.rename(bak, dst) raise os.remove(bak) CHUNKLEN = 65536 relinked = 0 savedbytes = 0 pos = 0 total = len(files) for f, sz in files: pos += 1 source = os.path.join(src, f) tgt = os.path.join(dst, f) # Binary mode, so that read() works correctly, especially on Windows sfp = file(source, 'rb') dfp = file(tgt, 'rb') sin = sfp.read(CHUNKLEN) while sin: din = dfp.read(CHUNKLEN) if sin != din: break sin = sfp.read(CHUNKLEN) sfp.close() dfp.close() if sin: ui.debug('not linkable: %s\n' % f) continue try: relinkfile(source, tgt) ui.progress(_('relinking'), pos, f, _('files'), total) relinked += 1 savedbytes += sz except OSError, inst: ui.warn('%s: %s\n' % (tgt, str(inst))) ui.progress(_('relinking'), None) ui.status(_('relinked %d files (%s reclaimed)\n') % (relinked, util.bytecount(savedbytes)))