contrib/perf.py

obsolete: order of magnitude speedup in _computebumpedset

Reminder: a changeset is said "bumped" if it tries to obsolete a immutable
          changeset.


The previous algorithm for computing bumped changeset was:

    1) Get all public changesets
    2) Find all they successors
    3) Search for stuff that are eligible for being "bumped"
       (mutable and non obsolete)

The entry size of this algorithm is `O(len(public))` which is mostly the same as
`O(len(repo))`. Even this this approach mean fewer obsolescence marker are
traveled, this is not very scalable.

The new algorithm is:

    1) For each potential bumped changesets (non obsolete mutable)
    2) iterate over precursors
    3) if a precursors is public. changeset is bumped

We travel more obsolescence marker, but the entry size is much smaller since
the amount of potential bumped should remains mostly stable with time `O(1)`.

On some confidential gigantic repo this move bumped computation from 15.19s to
0.46s (×33 speedup…). On "smaller" repo (mercurial, cubicweb's review) no
significant gain were seen. The additional traversal of obsolescence marker is
probably probably counter balance the advantage of it.

Other optimisation could be done in the future (eg: sharing precursors cache
for divergence detection)

# perf.py - performance test routines
'''helper extension to measure performance'''

from mercurial import cmdutil, scmutil, util, commands, obsolete
from mercurial import repoview, branchmap, merge, copies
import time, os, sys

cmdtable = {}
command = cmdutil.command(cmdtable)

def timer(func, title=None):
    results = []
    begin = time.time()
    count = 0
    while True:
        ostart = os.times()
        cstart = time.time()
        r = func()
        cstop = time.time()
        ostop = os.times()
        count += 1
        a, b = ostart, ostop
        results.append((cstop - cstart, b[0] - a[0], b[1]-a[1]))
        if cstop - begin > 3 and count >= 100:
            break
        if cstop - begin > 10 and count >= 3:
            break
    if title:
        sys.stderr.write("! %s\n" % title)
    if r:
        sys.stderr.write("! result: %s\n" % r)
    m = min(results)
    sys.stderr.write("! wall %f comb %f user %f sys %f (best of %d)\n"
                     % (m[0], m[1] + m[2], m[1], m[2], count))

@command('perfwalk')
def perfwalk(ui, repo, *pats):
    try:
        m = scmutil.match(repo[None], pats, {})
        timer(lambda: len(list(repo.dirstate.walk(m, [], True, False))))
    except Exception:
        try:
            m = scmutil.match(repo[None], pats, {})
            timer(lambda: len([b for a, b, c in repo.dirstate.statwalk([], m)]))
        except Exception:
            timer(lambda: len(list(cmdutil.walk(repo, pats, {}))))

@command('perfannotate')
def perfannotate(ui, repo, f):
    fc = repo['.'][f]
    timer(lambda: len(fc.annotate(True)))

@command('perfstatus',
         [('u', 'unknown', False,
           'ask status to look for unknown files')])
def perfstatus(ui, repo, **opts):
    #m = match.always(repo.root, repo.getcwd())
    #timer(lambda: sum(map(len, repo.dirstate.status(m, [], False, False,
    #                                                False))))
    timer(lambda: sum(map(len, repo.status(**opts))))

@command('perfaddremove')
def perfaddremove(ui, repo):
    try:
        oldquiet = repo.ui.quiet
        repo.ui.quiet = True
        timer(lambda: scmutil.addremove(repo, dry_run=True))
    finally:
        repo.ui.quiet = oldquiet

def clearcaches(cl):
    # behave somewhat consistently across internal API changes
    if util.safehasattr(cl, 'clearcaches'):
        cl.clearcaches()
    elif util.safehasattr(cl, '_nodecache'):
        from mercurial.node import nullid, nullrev
        cl._nodecache = {nullid: nullrev}
        cl._nodepos = None

@command('perfheads')
def perfheads(ui, repo):
    cl = repo.changelog
    def d():
        len(cl.headrevs())
        clearcaches(cl)
    timer(d)

@command('perftags')
def perftags(ui, repo):
    import mercurial.changelog
    import mercurial.manifest
    def t():
        repo.changelog = mercurial.changelog.changelog(repo.sopener)
        repo.manifest = mercurial.manifest.manifest(repo.sopener)
        repo._tags = None
        return len(repo.tags())
    timer(t)

@command('perfancestors')
def perfancestors(ui, repo):
    heads = repo.changelog.headrevs()
    def d():
        for a in repo.changelog.ancestors(heads):
            pass
    timer(d)

@command('perfancestorset')
def perfancestorset(ui, repo, revset):
    revs = repo.revs(revset)
    heads = repo.changelog.headrevs()
    def d():
        s = repo.changelog.ancestors(heads)
        for rev in revs:
            rev in s
    timer(d)

@command('perfdirs')
def perfdirs(ui, repo):
    dirstate = repo.dirstate
    'a' in dirstate
    def d():
        dirstate.dirs()
        del dirstate._dirs
    timer(d)

@command('perfdirstate')
def perfdirstate(ui, repo):
    "a" in repo.dirstate
    def d():
        repo.dirstate.invalidate()
        "a" in repo.dirstate
    timer(d)

@command('perfdirstatedirs')
def perfdirstatedirs(ui, repo):
    "a" in repo.dirstate
    def d():
        "a" in repo.dirstate._dirs
        del repo.dirstate._dirs
    timer(d)

@command('perfdirstatewrite')
def perfdirstatewrite(ui, repo):
    ds = repo.dirstate
    "a" in ds
    def d():
        ds._dirty = True
        ds.write()
    timer(d)

@command('perfmergecalculate',
         [('r', 'rev', '.', 'rev to merge against')])
def perfmergecalculate(ui, repo, rev):
    wctx = repo[None]
    rctx = scmutil.revsingle(repo, rev, rev)
    ancestor = wctx.ancestor(rctx)
    # we don't want working dir files to be stat'd in the benchmark, so prime
    # that cache
    wctx.dirty()
    def d():
        # acceptremote is True because we don't want prompts in the middle of
        # our benchmark
        merge.calculateupdates(repo, wctx, rctx, ancestor, False, False, False,
                               acceptremote=True)
    timer(d)

@command('perfpathcopies', [], "REV REV")
def perfpathcopies(ui, repo, rev1, rev2):
    ctx1 = scmutil.revsingle(repo, rev1, rev1)
    ctx2 = scmutil.revsingle(repo, rev2, rev2)
    def d():
        copies.pathcopies(ctx1, ctx2)
    timer(d)

@command('perfmanifest', [], 'REV')
def perfmanifest(ui, repo, rev):
    ctx = scmutil.revsingle(repo, rev, rev)
    t = ctx.manifestnode()
    def d():
        repo.manifest._mancache.clear()
        repo.manifest._cache = None
        repo.manifest.read(t)
    timer(d)

@command('perfchangeset')
def perfchangeset(ui, repo, rev):
    n = repo[rev].node()
    def d():
        repo.changelog.read(n)
        #repo.changelog._cache = None
    timer(d)

@command('perfindex')
def perfindex(ui, repo):
    import mercurial.revlog
    mercurial.revlog._prereadsize = 2**24 # disable lazy parser in old hg
    n = repo["tip"].node()
    def d():
        cl = mercurial.revlog.revlog(repo.sopener, "00changelog.i")
        cl.rev(n)
    timer(d)

@command('perfstartup')
def perfstartup(ui, repo):
    cmd = sys.argv[0]
    def d():
        os.system("HGRCPATH= %s version -q > /dev/null" % cmd)
    timer(d)

@command('perfparents')
def perfparents(ui, repo):
    nl = [repo.changelog.node(i) for i in xrange(1000)]
    def d():
        for n in nl:
            repo.changelog.parents(n)
    timer(d)

@command('perflookup')
def perflookup(ui, repo, rev):
    timer(lambda: len(repo.lookup(rev)))

@command('perfrevrange')
def perfrevrange(ui, repo, *specs):
    revrange = scmutil.revrange
    timer(lambda: len(revrange(repo, specs)))

@command('perfnodelookup')
def perfnodelookup(ui, repo, rev):
    import mercurial.revlog
    mercurial.revlog._prereadsize = 2**24 # disable lazy parser in old hg
    n = repo[rev].node()
    cl = mercurial.revlog.revlog(repo.sopener, "00changelog.i")
    def d():
        cl.rev(n)
        clearcaches(cl)
    timer(d)

@command('perflog',
         [('', 'rename', False, 'ask log to follow renames')])
def perflog(ui, repo, **opts):
    ui.pushbuffer()
    timer(lambda: commands.log(ui, repo, rev=[], date='', user='',
                               copies=opts.get('rename')))
    ui.popbuffer()

@command('perfmoonwalk')
def perfmoonwalk(ui, repo):
    """benchmark walking the changelog backwards

    This also loads the changelog data for each revision in the changelog.
    """
    def moonwalk():
        for i in xrange(len(repo), -1, -1):
            ctx = repo[i]
            ctx.branch() # read changelog data (in addition to the index)
    timer(moonwalk)

@command('perftemplating')
def perftemplating(ui, repo):
    ui.pushbuffer()
    timer(lambda: commands.log(ui, repo, rev=[], date='', user='',
                               template='{date|shortdate} [{rev}:{node|short}]'
                               ' {author|person}: {desc|firstline}\n'))
    ui.popbuffer()

@command('perfcca')
def perfcca(ui, repo):
    timer(lambda: scmutil.casecollisionauditor(ui, False, repo.dirstate))

@command('perffncacheload')
def perffncacheload(ui, repo):
    s = repo.store
    def d():
        s.fncache._load()
    timer(d)

@command('perffncachewrite')
def perffncachewrite(ui, repo):
    s = repo.store
    s.fncache._load()
    def d():
        s.fncache._dirty = True
        s.fncache.write()
    timer(d)

@command('perffncacheencode')
def perffncacheencode(ui, repo):
    s = repo.store
    s.fncache._load()
    def d():
        for p in s.fncache.entries:
            s.encode(p)
    timer(d)

@command('perfdiffwd')
def perfdiffwd(ui, repo):
    """Profile diff of working directory changes"""
    options = {
        'w': 'ignore_all_space',
        'b': 'ignore_space_change',
        'B': 'ignore_blank_lines',
        }

    for diffopt in ('', 'w', 'b', 'B', 'wB'):
        opts = dict((options[c], '1') for c in diffopt)
        def d():
            ui.pushbuffer()
            commands.diff(ui, repo, **opts)
            ui.popbuffer()
        title = 'diffopts: %s' % (diffopt and ('-' + diffopt) or 'none')
        timer(d, title)

@command('perfrevlog',
         [('d', 'dist', 100, 'distance between the revisions')],
         "[INDEXFILE]")
def perfrevlog(ui, repo, file_, **opts):
    from mercurial import revlog
    dist = opts['dist']
    def d():
        r = revlog.revlog(lambda fn: open(fn, 'rb'), file_)
        for x in xrange(0, len(r), dist):
            r.revision(r.node(x))

    timer(d)

@command('perfrevset',
         [('C', 'clear', False, 'clear volatile cache between each call.')],
         "REVSET")
def perfrevset(ui, repo, expr, clear=False):
    """benchmark the execution time of a revset

    Use the --clean option if need to evaluate the impact of build volatile
    revisions set cache on the revset execution. Volatile cache hold filtered
    and obsolete related cache."""
    def d():
        if clear:
            repo.invalidatevolatilesets()
        repo.revs(expr)
    timer(d)

@command('perfvolatilesets')
def perfvolatilesets(ui, repo, *names):
    """benchmark the computation of various volatile set

    Volatile set computes element related to filtering and obsolescence."""
    repo = repo.unfiltered()

    def getobs(name):
        def d():
            repo.invalidatevolatilesets()
            obsolete.getrevs(repo, name)
        return d

    allobs = sorted(obsolete.cachefuncs)
    if names:
        allobs = [n for n in allobs if n in names]

    for name in allobs:
        timer(getobs(name), title=name)

    def getfiltered(name):
        def d():
            repo.invalidatevolatilesets()
            repoview.filterrevs(repo, name)
        return d

    allfilter = sorted(repoview.filtertable)
    if names:
        allfilter = [n for n in allfilter if n in names]

    for name in allfilter:
        timer(getfiltered(name), title=name)

@command('perfbranchmap',
         [('f', 'full', False,
           'Includes build time of subset'),
         ])
def perfbranchmap(ui, repo, full=False):
    """benchmark the update of a branchmap

    This benchmarks the full repo.branchmap() call with read and write disabled
    """
    def getbranchmap(filtername):
        """generate a benchmark function for the filtername"""
        if filtername is None:
            view = repo
        else:
            view = repo.filtered(filtername)
        def d():
            if full:
                view._branchcaches.clear()
            else:
                view._branchcaches.pop(filtername, None)
            view.branchmap()
        return d
    # add filter in smaller subset to bigger subset
    possiblefilters = set(repoview.filtertable)
    allfilters = []
    while possiblefilters:
        for name in possiblefilters:
            subset = branchmap.subsettable.get(name)
            if subset not in possiblefilters:
                break
        else:
            assert False, 'subset cycle %s!' % possiblefilters
        allfilters.append(name)
        possiblefilters.remove(name)

    # warm the cache
    if not full:
        for name in allfilters:
            repo.filtered(name).branchmap()
    # add unfiltered
    allfilters.append(None)
    oldread = branchmap.read
    oldwrite = branchmap.branchcache.write
    try:
        branchmap.read = lambda repo: None
        branchmap.write = lambda repo: None
        for name in allfilters:
            timer(getbranchmap(name), title=str(name))
    finally:
        branchmap.read = oldread
        branchmap.branchcache.write = oldwrite