Mercurial > hg > mercurial-crew
changeset 28117:d394a1a3708a
perf: add perfrevlogrevision
As part of investigating performance improvements to revlog reading,
I needed a mechanism to measure every part of revlog reading so I knew
where time was spent and how effective optimizations were.
This patch implements a perf command for benchmarking the various
stages of reading a single revlog revision.
When executed against a manifest revision at the end of a 30,000+
long delta chain in mozilla-central, the command demonstrates that
~80% of time is spent in zlib decompression.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 20 Dec 2015 18:38:21 -0800 |
parents | 8914296e74a2 |
children | fe79f86099ae |
files | contrib/perf.py tests/test-contrib-perf.t |
diffstat | 2 files changed, 96 insertions(+), 1 deletions(-) [+] |
line wrap: on
line diff
--- a/contrib/perf.py +++ b/contrib/perf.py @@ -2,12 +2,14 @@ '''helper extension to measure performance''' from mercurial import cmdutil, scmutil, util, commands, obsolete -from mercurial import repoview, branchmap, merge, copies, error +from mercurial import repoview, branchmap, merge, copies, error, revlog +from mercurial import mdiff import time, os, sys import random import functools formatteropts = commands.formatteropts +revlogopts = commands.debugrevlogopts cmdtable = {} command = cmdutil.command(cmdtable) @@ -488,6 +490,96 @@ timer(d) fm.end() +@command('perfrevlogrevision', revlogopts + formatteropts + + [('', 'cache', False, 'use caches instead of clearing')], + '-c|-m|FILE REV') +def perfrevlogrevision(ui, repo, file_, rev=None, cache=None, **opts): + """Benchmark obtaining a revlog revision. + + Obtaining a revlog revision consists of roughly the following steps: + + 1. Compute the delta chain + 2. Obtain the raw chunks for that delta chain + 3. Decompress each raw chunk + 4. Apply binary patches to obtain fulltext + 5. Verify hash of fulltext + + This command measures the time spent in each of these phases. + """ + if opts.get('changelog') or opts.get('manifest'): + file_, rev = None, file_ + elif rev is None: + raise error.CommandError('perfrevlogrevision', 'invalid arguments') + + r = cmdutil.openrevlog(repo, 'perfrevlogrevision', file_, opts) + node = r.lookup(rev) + rev = r.rev(node) + + def dodeltachain(rev): + if not cache: + r.clearcaches() + r._deltachain(rev) + + def doread(chain): + if not cache: + r.clearcaches() + r._chunkraw(chain[0], chain[-1]) + + def dodecompress(data, chain): + if not cache: + r.clearcaches() + + start = r.start + length = r.length + inline = r._inline + iosize = r._io.size + buffer = util.buffer + offset = start(chain[0]) + + for rev in chain: + chunkstart = start(rev) + if inline: + chunkstart += (rev + 1) * iosize + chunklength = length(rev) + b = buffer(data, chunkstart - offset, chunklength) + revlog.decompress(b) + + def dopatch(text, bins): + if not cache: + r.clearcaches() + mdiff.patches(text, bins) + + def dohash(text): + if not cache: + r.clearcaches() + r._checkhash(text, node, rev) + + def dorevision(): + if not cache: + r.clearcaches() + r.revision(node) + + chain = r._deltachain(rev)[0] + data = r._chunkraw(chain[0], chain[-1]) + bins = r._chunks(chain) + text = str(bins[0]) + bins = bins[1:] + text = mdiff.patches(text, bins) + + benches = [ + (lambda: dorevision(), 'full'), + (lambda: dodeltachain(rev), 'deltachain'), + (lambda: doread(chain), 'read'), + (lambda: dodecompress(data, chain), 'decompress'), + (lambda: dopatch(text, bins), 'patch'), + (lambda: dohash(text), 'hash'), + ] + + for fn, title in benches: + timer, fm = gettimer(ui, opts) + timer(fn, title=title) + fm.end() + @command('perfrevset', [('C', 'clear', False, 'clear volatile cache between each call.'), ('', 'contexts', False, 'obtain changectx for each revision')]
--- a/tests/test-contrib-perf.t +++ b/tests/test-contrib-perf.t @@ -91,6 +91,8 @@ (no help text available) perfrawfiles (no help text available) perfrevlog (no help text available) + perfrevlogrevision + Benchmark obtaining a revlog revision. perfrevrange (no help text available) perfrevset benchmark the execution time of a revset perfstartup (no help text available) @@ -136,6 +138,7 @@ $ hg perfpathcopies 1 2 $ hg perfrawfiles 2 $ hg perfrevlog .hg/store/data/a.i + $ hg perfrevlogrevision -m 0 $ hg perfrevrange $ hg perfrevset 'all()' $ hg perfstartup