view tests/test-mq-guards.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.

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init
  $ hg qinit

  $ echo x > x
  $ hg ci -Ama
  adding x

  $ hg qnew a.patch
  $ echo a > a
  $ hg add a
  $ hg qrefresh

  $ hg qnew b.patch
  $ echo b > b
  $ hg add b
  $ hg qrefresh

  $ hg qnew c.patch
  $ echo c > c
  $ hg add c
  $ hg qrefresh

  $ hg qpop -a
  popping c.patch
  popping b.patch
  popping a.patch
  patch queue now empty


should fail

  $ hg qguard does-not-exist.patch +bleh
  abort: no patch named does-not-exist.patch
  [255]


should fail

  $ hg qguard +fail
  abort: no patches applied
  [255]

  $ hg qpush
  applying a.patch
  now at: a.patch

should guard a.patch

  $ hg qguard +a

should print +a

  $ hg qguard
  a.patch: +a
  $ hg qpop
  popping a.patch
  patch queue now empty


should fail

  $ hg qpush a.patch
  cannot push 'a.patch' - guarded by '+a'
  [1]

  $ hg qguard a.patch
  a.patch: +a

should push b.patch

  $ hg qpush
  applying b.patch
  now at: b.patch

  $ hg qpop
  popping b.patch
  patch queue now empty

test selection of an empty guard

  $ hg qselect ""
  abort: guard cannot be an empty string
  [255]
  $ hg qselect a
  number of unguarded, unapplied patches has changed from 2 to 3

should push a.patch

  $ hg qpush
  applying a.patch
  now at: a.patch

  $ hg qguard -- c.patch -a

should print -a

  $ hg qguard c.patch
  c.patch: -a


should skip c.patch

  $ hg qpush -a
  applying b.patch
  skipping c.patch - guarded by '-a'
  now at: b.patch
  $ hg qnext
  all patches applied
  [1]

should display b.patch

  $ hg qtop
  b.patch

  $ hg qguard -n c.patch

should push c.patch

  $ hg qpush -a
  applying c.patch
  now at: c.patch

  $ hg qpop -a
  popping c.patch
  popping b.patch
  popping a.patch
  patch queue now empty
  $ hg qselect -n
  guards deactivated
  number of unguarded, unapplied patches has changed from 3 to 2

should push all

  $ hg qpush -a
  applying b.patch
  applying c.patch
  now at: c.patch

  $ hg qpop -a
  popping c.patch
  popping b.patch
  patch queue now empty
  $ hg qguard a.patch +1
  $ hg qguard b.patch +2
  $ hg qselect 1
  number of unguarded, unapplied patches has changed from 1 to 2

should push a.patch, not b.patch

  $ hg qpush
  applying a.patch
  now at: a.patch
  $ hg qpush
  applying c.patch
  now at: c.patch
  $ hg qpop -a
  popping c.patch
  popping a.patch
  patch queue now empty

  $ hg qselect 2

should push b.patch

  $ hg qpush
  applying b.patch
  now at: b.patch
  $ hg qpush -a
  applying c.patch
  now at: c.patch
  $ hg qprev
  b.patch

Used to be an issue with holes in the patch sequence
So, put one hole on the base and ask for topmost patch.

  $ hg qtop
  c.patch
  $ hg qpop -a
  popping c.patch
  popping b.patch
  patch queue now empty

  $ hg qselect 1 2
  number of unguarded, unapplied patches has changed from 2 to 3

should push a.patch, b.patch

  $ hg qpush
  applying a.patch
  now at: a.patch
  $ hg qpush
  applying b.patch
  now at: b.patch
  $ hg qpop -a
  popping b.patch
  popping a.patch
  patch queue now empty

  $ hg qguard -- a.patch +1 +2 -3
  $ hg qselect 1 2 3
  number of unguarded, unapplied patches has changed from 3 to 2


list patches and guards

  $ hg qguard -l
  a.patch: +1 +2 -3
  b.patch: +2
  c.patch: unguarded

have at least one patch applied to test coloring

  $ hg qpush
  applying b.patch
  now at: b.patch

list patches and guards with color

  $ hg --config extensions.color= qguard --config color.mode=ansi \
  >     -l --color=always
  \x1b[0;30;1ma.patch\x1b[0m: \x1b[0;33m+1\x1b[0m \x1b[0;33m+2\x1b[0m \x1b[0;31m-3\x1b[0m (esc)
  \x1b[0;34;1;4mb.patch\x1b[0m: \x1b[0;33m+2\x1b[0m (esc)
  \x1b[0;30;1mc.patch\x1b[0m: \x1b[0;32munguarded\x1b[0m (esc)

should pop b.patch

  $ hg qpop
  popping b.patch
  patch queue now empty

list series

  $ hg qseries -v
  0 G a.patch
  1 U b.patch
  2 U c.patch

list guards

  $ hg qselect
  1
  2
  3

should push b.patch

  $ hg qpush
  applying b.patch
  now at: b.patch

  $ hg qpush -a
  applying c.patch
  now at: c.patch
  $ hg qselect -n --reapply -v
  guards deactivated
  popping guarded patches
  popping c.patch
  popping b.patch
  patch queue now empty
  reapplying unguarded patches
  skipping a.patch - guarded by '+1' '+2'
  skipping b.patch - guarded by '+2'
  skipping a.patch - guarded by '+1' '+2'
  skipping b.patch - guarded by '+2'
  applying c.patch
  patching file c
  adding c
  committing files:
  c
  committing manifest
  committing changelog
  now at: c.patch

guards in series file: +1 +2 -3

  $ hg qselect -s
  +1
  +2
  -3

should show c.patch

  $ hg qapplied
  c.patch

  $ hg qrename a.patch new.patch

should show :


new.patch: +1 +2 -3


b.patch: +2


c.patch: unguarded

  $ hg qguard -l
  new.patch: +1 +2 -3
  b.patch: +2
  c.patch: unguarded

  $ hg qnew d.patch
  $ hg qpop
  popping d.patch
  now at: c.patch

should show new.patch and b.patch as Guarded, c.patch as Applied


and d.patch as Unapplied

  $ hg qseries -v
  0 G new.patch
  1 G b.patch
  2 A c.patch
  3 U d.patch

qseries again, but with color

  $ hg --config extensions.color= --config color.mode=ansi qseries -v --color=always
  0 G \x1b[0;30;1mnew.patch\x1b[0m (esc)
  1 G \x1b[0;30;1mb.patch\x1b[0m (esc)
  2 A \x1b[0;34;1;4mc.patch\x1b[0m (esc)
  3 U \x1b[0;30;1md.patch\x1b[0m (esc)

  $ hg qguard d.patch +2

new.patch, b.patch: Guarded. c.patch: Applied. d.patch: Guarded.

  $ hg qseries -v
  0 G new.patch
  1 G b.patch
  2 A c.patch
  3 G d.patch

  $ qappunappv()
  > {
  >     for command in qapplied "qapplied -v" qunapplied "qunapplied -v"; do
  >         echo % hg $command
  >         hg $command
  >     done
  > }

  $ hg qpop -a
  popping c.patch
  patch queue now empty
  $ hg qguard -l
  new.patch: +1 +2 -3
  b.patch: +2
  c.patch: unguarded
  d.patch: +2
  $ qappunappv
  % hg qapplied
  % hg qapplied -v
  % hg qunapplied
  c.patch
  % hg qunapplied -v
  0 G new.patch
  1 G b.patch
  2 U c.patch
  3 G d.patch
  $ hg qselect 1
  number of unguarded, unapplied patches has changed from 1 to 2
  $ qappunappv
  % hg qapplied
  % hg qapplied -v
  % hg qunapplied
  new.patch
  c.patch
  % hg qunapplied -v
  0 U new.patch
  1 G b.patch
  2 U c.patch
  3 G d.patch
  $ hg qpush -a
  applying new.patch
  skipping b.patch - guarded by '+2'
  applying c.patch
  skipping d.patch - guarded by '+2'
  now at: c.patch
  $ qappunappv
  % hg qapplied
  new.patch
  c.patch
  % hg qapplied -v
  0 A new.patch
  1 G b.patch
  2 A c.patch
  % hg qunapplied
  % hg qunapplied -v
  3 G d.patch
  $ hg qselect 2
  number of unguarded, unapplied patches has changed from 0 to 1
  $ qappunappv
  % hg qapplied
  new.patch
  c.patch
  % hg qapplied -v
  0 A new.patch
  1 U b.patch
  2 A c.patch
  % hg qunapplied
  d.patch
  % hg qunapplied -v
  3 U d.patch

  $ for patch in `hg qseries`; do
  >     echo % hg qapplied $patch
  >     hg qapplied $patch
  >     echo % hg qunapplied $patch
  >     hg qunapplied $patch
  > done
  % hg qapplied new.patch
  new.patch
  % hg qunapplied new.patch
  b.patch
  d.patch
  % hg qapplied b.patch
  new.patch
  % hg qunapplied b.patch
  d.patch
  % hg qapplied c.patch
  new.patch
  c.patch
  % hg qunapplied c.patch
  d.patch
  % hg qapplied d.patch
  new.patch
  c.patch
  % hg qunapplied d.patch


hg qseries -m: only b.patch should be shown
the guards file was not ignored in the past

  $ hg qdelete -k b.patch
  $ hg qseries -m
  b.patch

hg qseries -m with color

  $ hg --config extensions.color= --config color.mode=ansi qseries -m --color=always
  \x1b[0;31;1mb.patch\x1b[0m (esc)


excercise corner cases in "qselect --reapply"

  $ hg qpop -a
  popping c.patch
  popping new.patch
  patch queue now empty
  $ hg qguard -- new.patch -not-new
  $ hg qguard -- c.patch -not-c
  $ hg qguard -- d.patch -not-d
  $ hg qpush -a
  applying new.patch
  applying c.patch
  applying d.patch
  patch d.patch is empty
  now at: d.patch
  $ hg qguard -l
  new.patch: -not-new
  c.patch: -not-c
  d.patch: -not-d
  $ hg qselect --reapply not-d
  popping guarded patches
  popping d.patch
  now at: c.patch
  reapplying unguarded patches
  cannot push 'd.patch' - guarded by '-not-d'
  $ hg qser -v
  0 A new.patch
  1 A c.patch
  2 G d.patch
  $ hg qselect --reapply -n
  guards deactivated
  $ hg qpush
  applying d.patch
  patch d.patch is empty
  now at: d.patch
  $ hg qser -v
  0 A new.patch
  1 A c.patch
  2 A d.patch
  $ hg qselect --reapply not-c
  popping guarded patches
  popping d.patch
  popping c.patch
  now at: new.patch
  reapplying unguarded patches
  applying d.patch
  patch d.patch is empty
  now at: d.patch
  $ hg qser -v
  0 A new.patch
  1 G c.patch
  2 A d.patch
  $ hg qselect --reapply not-new
  popping guarded patches
  popping d.patch
  popping new.patch
  patch queue now empty
  reapplying unguarded patches
  applying c.patch
  applying d.patch
  patch d.patch is empty
  now at: d.patch
  $ hg qser -v
  0 G new.patch
  1 A c.patch
  2 A d.patch

test that qselect shows "number of guarded, applied patches" correctly

  $ hg qimport -q -e b.patch
  adding b.patch to series file
  $ hg qguard -- b.patch -not-b
  $ hg qpop -a -q
  patch queue now empty
  $ hg qunapplied -v
  0 G new.patch
  1 U c.patch
  2 U d.patch
  3 U b.patch
  $ hg qselect not-new not-c
  number of unguarded, unapplied patches has changed from 3 to 2
  $ hg qpush -q -a
  patch d.patch is empty
  now at: b.patch

  $ hg qapplied -v
  0 G new.patch
  1 G c.patch
  2 A d.patch
  3 A b.patch
  $ hg qselect --none
  guards deactivated
  $ hg qselect not-new not-c not-d
  number of guarded, applied patches has changed from 0 to 1

test that "qselect --reapply" reapplies patches successfully when the
already applied patch becomes unguarded and it follows the already
guarded (= not yet applied) one.

  $ hg qpop -q -a
  patch queue now empty
  $ hg qselect not-new not-c
  number of unguarded, unapplied patches has changed from 1 to 2
  $ hg qpush -q -a
  patch d.patch is empty
  now at: b.patch
  $ hg qapplied -v
  0 G new.patch
  1 G c.patch
  2 A d.patch
  3 A b.patch
  $ hg qselect -q --reapply not-c not-b
  now at: d.patch
  cannot push 'b.patch' - guarded by '-not-b'
  $ hg qseries -v
  0 U new.patch
  1 G c.patch
  2 A d.patch
  3 G b.patch

test that "qselect --reapply" checks applied patches correctly when no
applied patches becomes guarded but some of unapplied ones become
unguarded.

  $ hg qpop -q -a
  patch queue now empty
  $ hg qselect not-new not-c not-d
  number of unguarded, unapplied patches has changed from 2 to 1
  $ hg qpush -q -a
  now at: b.patch
  $ hg qapplied -v
  0 G new.patch
  1 G c.patch
  2 G d.patch
  3 A b.patch
  $ hg qselect -q --reapply not-new not-c
  $ hg qseries -v
  0 G new.patch
  1 G c.patch
  2 U d.patch
  3 A b.patch