Mercurial > hg
view contrib/revsetbenchmarks.py @ 49000:dd6b67d5c256 stable
rust: fix unsound `OwningDirstateMap`
As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.
The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.
I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.
In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.
Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.
Differential Revision: https://phab.mercurial-scm.org/D12429
author | Raphaël Gomès <rgomes@octobus.net> |
---|---|
date | Tue, 05 Apr 2022 10:55:28 +0200 |
parents | c102b704edb5 |
children | 6000f5b25c9b |
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#!/usr/bin/env python3 # Measure the performance of a list of revsets against multiple revisions # defined by parameter. Checkout one by one and run perfrevset with every # revset in the list to benchmark its performance. # # You should run this from the root of your mercurial repository. # # call with --help for details from __future__ import absolute_import, print_function import math import optparse # cannot use argparse, python 2.7 only import os import re import subprocess import sys DEFAULTVARIANTS = [ 'plain', 'min', 'max', 'first', 'last', 'reverse', 'reverse+first', 'reverse+last', 'sort', 'sort+first', 'sort+last', ] def check_output(*args, **kwargs): kwargs.setdefault('stderr', subprocess.PIPE) kwargs.setdefault('stdout', subprocess.PIPE) proc = subprocess.Popen(*args, **kwargs) output, error = proc.communicate() if proc.returncode != 0: raise subprocess.CalledProcessError(proc.returncode, ' '.join(args[0])) return output def update(rev): """update the repo to a revision""" try: subprocess.check_call(['hg', 'update', '--quiet', '--check', str(rev)]) check_output( ['make', 'local'], stderr=None ) # suppress output except for error/warning except subprocess.CalledProcessError as exc: print('update to revision %s failed, aborting' % rev, file=sys.stderr) sys.exit(exc.returncode) def hg(cmd, repo=None): """run a mercurial command <cmd> is the list of command + argument, <repo> is an optional repository path to run this command in.""" fullcmd = ['./hg'] if repo is not None: fullcmd += ['-R', repo] fullcmd += [ '--config', 'extensions.perf=' + os.path.join(contribdir, 'perf.py'), ] fullcmd += cmd return check_output(fullcmd, stderr=subprocess.STDOUT) def perf(revset, target=None, contexts=False): """run benchmark for this very revset""" try: args = ['perfrevset'] if contexts: args.append('--contexts') args.append('--') args.append(revset) output = hg(args, repo=target) return parseoutput(output) except subprocess.CalledProcessError as exc: print( 'abort: cannot run revset benchmark: %s' % exc.cmd, file=sys.stderr ) if getattr(exc, 'output', None) is None: # no output before 2.7 print('(no output)', file=sys.stderr) else: print(exc.output, file=sys.stderr) return None outputre = re.compile( br'! wall (\d+.\d+) comb (\d+.\d+) user (\d+.\d+) ' br'sys (\d+.\d+) \(best of (\d+)\)' ) def parseoutput(output): """parse a textual output into a dict We cannot just use json because we want to compare with old versions of Mercurial that may not support json output. """ match = outputre.search(output) if not match: print('abort: invalid output:', file=sys.stderr) print(output, file=sys.stderr) sys.exit(1) return { 'comb': float(match.group(2)), 'count': int(match.group(5)), 'sys': float(match.group(3)), 'user': float(match.group(4)), 'wall': float(match.group(1)), } def printrevision(rev): """print data about a revision""" sys.stdout.write("Revision ") sys.stdout.flush() subprocess.check_call( [ 'hg', 'log', '--rev', str(rev), '--template', '{if(tags, " ({tags})")} ' '{rev}:{node|short}: {desc|firstline}\n', ] ) def idxwidth(nbidx): """return the max width of number used for index This is similar to log10(nbidx), but we use custom code here because we start with zero and we'd rather not deal with all the extra rounding business that log10 would imply. """ nbidx -= 1 # starts at 0 idxwidth = 0 while nbidx: idxwidth += 1 nbidx //= 10 if not idxwidth: idxwidth = 1 return idxwidth def getfactor(main, other, field, sensitivity=0.05): """return the relative factor between values for 'field' in main and other Return None if the factor is insignificant (less than <sensitivity> variation).""" factor = 1 if main is not None: factor = other[field] / main[field] low, high = 1 - sensitivity, 1 + sensitivity if low < factor < high: return None return factor def formatfactor(factor): """format a factor into a 4 char string 22% 156% x2.4 x23 x789 x1e4 x5x7 """ if factor is None: return ' ' elif factor < 2: return '%3i%%' % (factor * 100) elif factor < 10: return 'x%3.1f' % factor elif factor < 1000: return '%4s' % ('x%i' % factor) else: order = int(math.log(factor)) + 1 while math.log(factor) > 1: factor //= 0 return 'x%ix%i' % (factor, order) def formattiming(value): """format a value to strictly 8 char, dropping some precision if needed""" if value < 10 ** 7: return ('%.6f' % value)[:8] else: # value is HUGE very unlikely to happen (4+ month run) return '%i' % value _marker = object() def printresult(variants, idx, data, maxidx, verbose=False, reference=_marker): """print a line of result to stdout""" mask = '%%0%ii) %%s' % idxwidth(maxidx) out = [] for var in variants: if data[var] is None: out.append('error ') out.append(' ' * 4) continue out.append(formattiming(data[var]['wall'])) if reference is not _marker: factor = None if reference is not None: factor = getfactor(reference[var], data[var], 'wall') out.append(formatfactor(factor)) if verbose: out.append(formattiming(data[var]['comb'])) out.append(formattiming(data[var]['user'])) out.append(formattiming(data[var]['sys'])) out.append('%6d' % data[var]['count']) print(mask % (idx, ' '.join(out))) def printheader(variants, maxidx, verbose=False, relative=False): header = [' ' * (idxwidth(maxidx) + 1)] for var in variants: if not var: var = 'iter' if len(var) > 8: var = var[:3] + '..' + var[-3:] header.append('%-8s' % var) if relative: header.append(' ') if verbose: header.append('%-8s' % 'comb') header.append('%-8s' % 'user') header.append('%-8s' % 'sys') header.append('%6s' % 'count') print(' '.join(header)) def getrevs(spec): """get the list of rev matched by a revset""" try: out = check_output(['hg', 'log', '--template={rev}\n', '--rev', spec]) except subprocess.CalledProcessError as exc: print("abort, can't get revision from %s" % spec, file=sys.stderr) sys.exit(exc.returncode) return [r for r in out.split() if r] def applyvariants(revset, variant): if variant == 'plain': return revset for var in variant.split('+'): revset = '%s(%s)' % (var, revset) return revset helptext = """This script will run multiple variants of provided revsets using different revisions in your mercurial repository. After the benchmark are run summary output is provided. Use it to demonstrate speed improvements or pin point regressions. Revsets to run are specified in a file (or from stdin), one revsets per line. Line starting with '#' will be ignored, allowing insertion of comments.""" parser = optparse.OptionParser( usage="usage: %prog [options] <revs>", description=helptext ) parser.add_option( "-f", "--file", help="read revset from FILE (stdin if omitted)", metavar="FILE", ) parser.add_option("-R", "--repo", help="run benchmark on REPO", metavar="REPO") parser.add_option( "-v", "--verbose", action='store_true', help="display all timing data (not just best total time)", ) parser.add_option( "", "--variants", default=','.join(DEFAULTVARIANTS), help="comma separated list of variant to test " "(eg: plain,min,sorted) (plain = no modification)", ) parser.add_option( '', '--contexts', action='store_true', help='obtain changectx from results instead of integer revs', ) (options, args) = parser.parse_args() if not args: parser.print_help() sys.exit(255) # the directory where both this script and the perf.py extension live. contribdir = os.path.dirname(__file__) revsetsfile = sys.stdin if options.file: revsetsfile = open(options.file) revsets = [l.strip() for l in revsetsfile if not l.startswith('#')] revsets = [l for l in revsets if l] print("Revsets to benchmark") print("----------------------------") for idx, rset in enumerate(revsets): print("%i) %s" % (idx, rset)) print("----------------------------") print() revs = [] for a in args: revs.extend(getrevs(a)) variants = options.variants.split(',') results = [] for r in revs: print("----------------------------") printrevision(r) print("----------------------------") update(r) res = [] results.append(res) printheader(variants, len(revsets), verbose=options.verbose) for idx, rset in enumerate(revsets): varres = {} for var in variants: varrset = applyvariants(rset, var) data = perf(varrset, target=options.repo, contexts=options.contexts) varres[var] = data res.append(varres) printresult( variants, idx, varres, len(revsets), verbose=options.verbose ) sys.stdout.flush() print("----------------------------") print( """ Result by revset ================ """ ) print('Revision:') for idx, rev in enumerate(revs): sys.stdout.write('%i) ' % idx) sys.stdout.flush() printrevision(rev) print() print() for ridx, rset in enumerate(revsets): print("revset #%i: %s" % (ridx, rset)) printheader(variants, len(results), verbose=options.verbose, relative=True) ref = None for idx, data in enumerate(results): printresult( variants, idx, data[ridx], len(results), verbose=options.verbose, reference=ref, ) ref = data[ridx] print()