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view tests/test-completion.t @ 30442:41a8106789ca
util: implement zstd compression engine
Now that zstd is vendored and being built (in some configurations), we
can implement a compression engine for zstd!
The zstd engine is a little different from existing engines. Because
it may not always be present, we have to defer load the module in case
importing it fails. We facilitate this via a cached property that holds
a reference to the module or None. The "available" method is
implemented to reflect reality.
The zstd engine declares its ability to handle bundles using the
"zstd" human name and the "ZS" internal name. The latter was chosen
because internal names are 2 characters (by only convention I think)
and "ZS" seems reasonable.
The engine, like others, supports specifying the compression level.
However, there are no consumers of this API that yet pass in that
argument. I have plans to change that, so stay tuned.
Since all we need to do to support bundle generation with a new
compression engine is implement and register the compression engine,
bundle generation with zstd "just works!" Tests demonstrating this
have been added.
How does performance of zstd for bundle generation compare? On the
mozilla-unified repo, `hg bundle --all -t <engine>-v2` yields the
following on my i7-6700K on Linux:
engine CPU time bundle size vs orig size throughput
none 97.0s 4,054,405,584 100.0% 41.8 MB/s
bzip2 (l=9) 393.6s 975,343,098 24.0% 10.3 MB/s
gzip (l=6) 184.0s 1,140,533,074 28.1% 22.0 MB/s
zstd (l=1) 108.2s 1,119,434,718 27.6% 37.5 MB/s
zstd (l=2) 111.3s 1,078,328,002 26.6% 36.4 MB/s
zstd (l=3) 113.7s 1,011,823,727 25.0% 35.7 MB/s
zstd (l=4) 116.0s 1,008,965,888 24.9% 35.0 MB/s
zstd (l=5) 121.0s 977,203,148 24.1% 33.5 MB/s
zstd (l=6) 131.7s 927,360,198 22.9% 30.8 MB/s
zstd (l=7) 139.0s 912,808,505 22.5% 29.2 MB/s
zstd (l=12) 198.1s 854,527,714 21.1% 20.5 MB/s
zstd (l=18) 681.6s 789,750,690 19.5% 5.9 MB/s
On compression, zstd for bundle generation delivers:
* better compression than gzip with significantly less CPU utilization
* better than bzip2 compression ratios while still being significantly
faster than gzip
* ability to aggressively tune compression level to achieve
significantly smaller bundles
That last point is important. With clone bundles, a server can
pre-generate a bundle file, upload it to a static file server, and
redirect clients to transparently download it during clone. The server
could choose to produce a zstd bundle with the highest compression
settings possible. This would take a very long time - a magnitude
longer than a typical zstd bundle generation - but the result would
be hundreds of megabytes smaller! For the clone volume we do at
Mozilla, this could translate to petabytes of bandwidth savings
per year and faster clones (due to smaller transfer size).
I don't have detailed numbers to report on decompression. However,
zstd decompression is fast: >1 GB/s output throughput on this machine,
even through the Python bindings. And it can do that regardless of the
compression level of the input. By the time you have enough data to
worry about overhead of decompression, you have plenty of other things
to worry about performance wise.
zstd is wins all around. I can't wait to implement support for it
on the wire protocol and in revlogs.
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Fri, 11 Nov 2016 01:10:07 -0800 |
| parents | 80fef5251099 |
| children | eaa5607132a2 |
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Show all commands except debug commands $ hg debugcomplete add addremove annotate archive backout bisect bookmarks branch branches bundle cat clone commit config copy diff export files forget graft grep heads help identify import incoming init locate log manifest merge outgoing parents paths phase pull push recover remove rename resolve revert rollback root serve status summary tag tags tip unbundle update verify version Show all commands that start with "a" $ hg debugcomplete a add addremove annotate archive Do not show debug commands if there are other candidates $ hg debugcomplete d diff Show debug commands if there are no other candidates $ hg debugcomplete debug debugancestor debugapplystreamclonebundle debugbuilddag debugbundle debugcheckstate debugcommands debugcomplete debugconfig debugcreatestreamclonebundle debugdag debugdata debugdate debugdeltachain debugdirstate debugdiscovery debugextensions debugfileset debugfsinfo debuggetbundle debugignore debugindex debugindexdot debuginstall debugknown debuglabelcomplete debuglocks debugmergestate debugnamecomplete debugobsolete debugpathcomplete debugpushkey debugpvec debugrebuilddirstate debugrebuildfncache debugrename debugrevlog debugrevspec debugsetparents debugsub debugsuccessorssets debugtemplate debugwalk debugwireargs Do not show the alias of a debug command if there are other candidates (this should hide rawcommit) $ hg debugcomplete r recover remove rename resolve revert rollback root Show the alias of a debug command if there are no other candidates $ hg debugcomplete rawc Show the global options $ hg debugcomplete --options | sort --config --cwd --debug --debugger --encoding --encodingmode --help --hidden --noninteractive --profile --quiet --repository --time --traceback --verbose --version -R -h -q -v -y Show the options for the "serve" command $ hg debugcomplete --options serve | sort --accesslog --address --certificate --cmdserver --config --cwd --daemon --daemon-postexec --debug --debugger --encoding --encodingmode --errorlog --help --hidden --ipv6 --name --noninteractive --pid-file --port --prefix --profile --quiet --repository --stdio --style --templates --time --traceback --verbose --version --web-conf -6 -A -E -R -a -d -h -n -p -q -t -v -y Show an error if we use --options with an ambiguous abbreviation $ hg debugcomplete --options s hg: command 's' is ambiguous: serve showconfig status summary [255] Show all commands + options $ hg debugcommands add: include, exclude, subrepos, dry-run annotate: rev, follow, no-follow, text, user, file, date, number, changeset, line-number, ignore-all-space, ignore-space-change, ignore-blank-lines, include, exclude, template clone: noupdate, updaterev, rev, branch, pull, uncompressed, ssh, remotecmd, insecure commit: addremove, close-branch, amend, secret, edit, interactive, include, exclude, message, logfile, date, user, subrepos diff: rev, change, text, git, nodates, noprefix, show-function, reverse, ignore-all-space, ignore-space-change, ignore-blank-lines, unified, stat, root, include, exclude, subrepos export: output, switch-parent, rev, text, git, nodates forget: include, exclude init: ssh, remotecmd, insecure log: follow, follow-first, date, copies, keyword, rev, removed, only-merges, user, only-branch, branch, prune, patch, git, limit, no-merges, stat, graph, style, template, include, exclude merge: force, rev, preview, tool pull: update, force, rev, bookmark, branch, ssh, remotecmd, insecure push: force, rev, bookmark, branch, new-branch, ssh, remotecmd, insecure remove: after, force, subrepos, include, exclude serve: accesslog, daemon, daemon-postexec, errorlog, port, address, prefix, name, web-conf, webdir-conf, pid-file, stdio, cmdserver, templates, style, ipv6, certificate status: all, modified, added, removed, deleted, clean, unknown, ignored, no-status, copies, print0, rev, change, include, exclude, subrepos, template summary: remote update: clean, check, date, rev, tool addremove: similarity, subrepos, include, exclude, dry-run archive: no-decode, prefix, rev, type, subrepos, include, exclude backout: merge, commit, no-commit, parent, rev, edit, tool, include, exclude, message, logfile, date, user bisect: reset, good, bad, skip, extend, command, noupdate bookmarks: force, rev, delete, rename, inactive, template branch: force, clean branches: active, closed, template bundle: force, rev, branch, base, all, type, ssh, remotecmd, insecure cat: output, rev, decode, include, exclude config: untrusted, edit, local, global, template copy: after, force, include, exclude, dry-run debugancestor: debugapplystreamclonebundle: debugbuilddag: mergeable-file, overwritten-file, new-file debugbundle: all, spec debugcheckstate: debugcommands: debugcomplete: options debugcreatestreamclonebundle: debugdag: tags, branches, dots, spaces debugdata: changelog, manifest, dir debugdate: extended debugdeltachain: changelog, manifest, dir, template debugdirstate: nodates, datesort debugdiscovery: old, nonheads, ssh, remotecmd, insecure debugextensions: template debugfileset: rev debugfsinfo: debuggetbundle: head, common, type debugignore: debugindex: changelog, manifest, dir, format debugindexdot: changelog, manifest, dir debuginstall: template debugknown: debuglabelcomplete: debuglocks: force-lock, force-wlock debugmergestate: debugnamecomplete: debugobsolete: flags, record-parents, rev, index, delete, date, user, template debugpathcomplete: full, normal, added, removed debugpushkey: debugpvec: debugrebuilddirstate: rev, minimal debugrebuildfncache: debugrename: rev debugrevlog: changelog, manifest, dir, dump debugrevspec: optimize, show-stage, no-optimized, verify-optimized debugsetparents: debugsub: rev debugsuccessorssets: debugtemplate: rev, define debugwalk: include, exclude debugwireargs: three, four, five, ssh, remotecmd, insecure files: rev, print0, include, exclude, template, subrepos graft: rev, continue, edit, log, force, currentdate, currentuser, date, user, tool, dry-run grep: print0, all, text, follow, ignore-case, files-with-matches, line-number, rev, user, date, template, include, exclude heads: rev, topo, active, closed, style, template help: extension, command, keyword, system identify: rev, num, id, branch, tags, bookmarks, ssh, remotecmd, insecure import: strip, base, edit, force, no-commit, bypass, partial, exact, prefix, import-branch, message, logfile, date, user, similarity incoming: force, newest-first, bundle, rev, bookmarks, branch, patch, git, limit, no-merges, stat, graph, style, template, ssh, remotecmd, insecure, subrepos locate: rev, print0, fullpath, include, exclude manifest: rev, all, template outgoing: force, rev, newest-first, bookmarks, branch, patch, git, limit, no-merges, stat, graph, style, template, ssh, remotecmd, insecure, subrepos parents: rev, style, template paths: template phase: public, draft, secret, force, rev recover: rename: after, force, include, exclude, dry-run resolve: all, list, mark, unmark, no-status, tool, include, exclude, template revert: all, date, rev, no-backup, interactive, include, exclude, dry-run rollback: dry-run, force root: tag: force, local, rev, remove, edit, message, date, user tags: template tip: patch, git, style, template unbundle: update verify: version: template $ hg init a $ cd a $ echo fee > fee $ hg ci -q -Amfee $ hg tag fee $ mkdir fie $ echo dead > fie/dead $ echo live > fie/live $ hg bookmark fo $ hg branch -q fie $ hg ci -q -Amfie $ echo fo > fo $ hg branch -qf default $ hg ci -q -Amfo $ echo Fum > Fum $ hg ci -q -AmFum $ hg bookmark Fum Test debugpathcomplete $ hg debugpathcomplete f fee fie fo $ hg debugpathcomplete -f f fee fie/dead fie/live fo $ hg rm Fum $ hg debugpathcomplete -r F Fum Test debugnamecomplete $ hg debugnamecomplete Fum default fee fie fo tip $ hg debugnamecomplete f fee fie fo