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view tests/fakedirstatewritetime.py @ 42743:8c9a6adec67a
rust-discovery: using the children cache in add_missing
The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.
The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.
This is a case where staying on the same side of the interface
between the two languages has clear benefits.
On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.
For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:
Rust version with simple iteration
addcommons: 57.287us
first undecided computation: 184.278334ms
first children cache computation: 131.056us
addmissings iteration: 42.766us
first addinfo total: 185.24 ms
Python + C version
first addcommons: 0.29 ms
addcommons 0.21 ms
first undecided computation 191.35 ms
addmissings 45.75 ms
first addinfo total: 237.77 ms
On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:
Rust version:
first undecided computation: 293.842629ms
first children cache computation: 407.911297ms
addmissings iteration: 34.312869ms
first addinfo total: 776.02 ms
taking initial sample
query 2: sampling time: 1318.38 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings: 143.062us
Python + C version:
first undecided computation 298.13 ms
addmissings 80.13 ms
first addinfo total: 399.62 ms
taking initial sample
query 2: sampling time: 3957.23 ms
query 2; still undecided: 1005013, sample size is: 200
addmissings 52.88 ms
Differential Revision: https://phab.mercurial-scm.org/D6428
author | Georges Racinet <georges.racinet@octobus.net> |
---|---|
date | Tue, 16 Apr 2019 01:16:39 +0200 |
parents | 9c6c0f736e1d |
children | 760a7851e9ba |
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# extension to emulate invoking 'dirstate.write()' at the time # specified by '[fakedirstatewritetime] fakenow', only when # 'dirstate.write()' is invoked via functions below: # # - 'workingctx._poststatusfixup()' (= 'repo.status()') # - 'committablectx.markcommitted()' from __future__ import absolute_import from mercurial import ( context, dirstate, extensions, policy, registrar, ) from mercurial.utils import dateutil try: from mercurial import rustext rustext.__name__ # force actual import (see hgdemandimport) except ImportError: rustext = None configtable = {} configitem = registrar.configitem(configtable) configitem(b'fakedirstatewritetime', b'fakenow', default=None, ) parsers = policy.importmod(r'parsers') def pack_dirstate(fakenow, orig, dmap, copymap, pl, now): # execute what original parsers.pack_dirstate should do actually # for consistency actualnow = int(now) for f, e in dmap.items(): if e[0] == 'n' and e[3] == actualnow: e = parsers.dirstatetuple(e[0], e[1], e[2], -1) dmap[f] = e return orig(dmap, copymap, pl, fakenow) def fakewrite(ui, func): # fake "now" of 'pack_dirstate' only if it is invoked while 'func' fakenow = ui.config(b'fakedirstatewritetime', b'fakenow') if not fakenow: # Execute original one, if fakenow isn't configured. This is # useful to prevent subrepos from executing replaced one, # because replacing 'parsers.pack_dirstate' is also effective # in subrepos. return func() # parsing 'fakenow' in YYYYmmddHHMM format makes comparison between # 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy fakenow = dateutil.parsedate(fakenow, [b'%Y%m%d%H%M'])[0] if rustext is not None: orig_module = rustext.dirstate orig_pack_dirstate = rustext.dirstate.pack_dirstate else: orig_module = parsers orig_pack_dirstate = parsers.pack_dirstate orig_dirstate_getfsnow = dirstate._getfsnow wrapper = lambda *args: pack_dirstate(fakenow, orig_pack_dirstate, *args) orig_module.pack_dirstate = wrapper dirstate._getfsnow = lambda *args: fakenow try: return func() finally: orig_module.pack_dirstate = orig_pack_dirstate dirstate._getfsnow = orig_dirstate_getfsnow def _poststatusfixup(orig, workingctx, status, fixup): ui = workingctx.repo().ui return fakewrite(ui, lambda : orig(workingctx, status, fixup)) def markcommitted(orig, committablectx, node): ui = committablectx.repo().ui return fakewrite(ui, lambda : orig(committablectx, node)) def extsetup(ui): extensions.wrapfunction(context.workingctx, '_poststatusfixup', _poststatusfixup) extensions.wrapfunction(context.workingctx, 'markcommitted', markcommitted)