tests/test-profile.t

help: document bundle specifications

I softly formalized the concept of a "bundle specification" a while
ago when I was working on clone bundles and stream clone bundles and
wanted a more robust way to define what exactly is in a bundle file.

The concept has existed for a while. Since it is part of the clone
bundles feature and exposed to the user via the "-t" argument to
`hg bundle`, it is something we need to support for the long haul.

After the 4.1 release, I heard a few people comment that they didn't
realize you could generate zstd bundles with `hg bundle`. I'm
partially to blame for not documenting it in bundle's docstring.

Additionally, I added a hacky, experimental feature for controlling
the compression level of bundles in 76104a4899ad. As the commit
message says, I went with a quick and dirty solution out of time
constraints. Furthermore, I wanted to eventually store this
configuration in the "bundlespec" so it could be made more flexible.

Given:

a) bundlespecs are here to stay
b) we don't have great documentation over what they are, despite being
   a user-facing feature
c) the list of available compression engines and their behavior isn't
   exposed
d) we need an extensible place to modify behavior of compression
   engines

I want to move forward with formalizing bundlespecs as a user-facing
feature. This commit does that by introducing a "bundlespec" help
page. Leaning on the just-added compression engine documentation
and API, the topic also conveniently lists available compression
engines and details about them. This makes features like zstd
bundle compression more discoverable. e.g. you can now
`hg help -k zstd` and it lists the "bundlespec" topic.

test --time

  $ hg --time help -q help 2>&1 | grep time > /dev/null
  $ hg init a
  $ cd a

#if lsprof

test --profile

  $ prof='hg --config profiling.type=ls --profile'

  $ $prof st 2>../out
  $ grep CallCount ../out > /dev/null || cat ../out

  $ $prof --config profiling.output=../out st
  $ grep CallCount ../out > /dev/null || cat ../out

  $ $prof --config profiling.output=blackbox --config extensions.blackbox= st
  $ grep CallCount .hg/blackbox.log > /dev/null || cat .hg/blackbox.log

  $ $prof --config profiling.format=text st 2>../out
  $ grep CallCount ../out > /dev/null || cat ../out

  $ echo "[profiling]" >> $HGRCPATH
  $ echo "format=kcachegrind" >> $HGRCPATH

  $ $prof st 2>../out
  $ grep 'events: Ticks' ../out > /dev/null || cat ../out

  $ $prof --config profiling.output=../out st
  $ grep 'events: Ticks' ../out > /dev/null || cat ../out

#endif

#if lsprof serve

Profiling of HTTP requests works

  $ $prof --config profiling.format=text --config profiling.output=../profile.log serve -d -p $HGPORT --pid-file ../hg.pid -A ../access.log
  $ cat ../hg.pid >> $DAEMON_PIDS
  $ hg -q clone -U http://localhost:$HGPORT ../clone

A single profile is logged because file logging doesn't append
  $ grep CallCount ../profile.log | wc -l
  \s*1 (re)

#endif

Install an extension that can sleep and guarantee a profiler has time to run

  $ cat >> sleepext.py << EOF
  > import time
  > from mercurial import cmdutil, commands
  > cmdtable = {}
  > command = cmdutil.command(cmdtable)
  > @command('sleep', [], 'hg sleep')
  > def sleep(ui, *args, **kwargs):
  >     time.sleep(0.1)
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > sleep = `pwd`/sleepext.py
  > EOF

statistical profiler works

  $ hg --profile sleep 2>../out
  $ grep Sample ../out
  Sample count: \d+ (re)

Various statprof formatters work

  $ hg --profile --config profiling.statformat=byline sleep 2>../out
  $ head -n 1 ../out
    %   cumulative      self          
  $ grep Sample ../out
  Sample count: \d+ (re)

  $ hg --profile --config profiling.statformat=bymethod sleep 2>../out
  $ head -n 1 ../out
    %   cumulative      self          
  $ grep Sample ../out
  Sample count: \d+ (re)

  $ hg --profile --config profiling.statformat=hotpath sleep 2>../out
  $ grep Sample ../out
  Sample count: \d+ (re)

  $ hg --profile --config profiling.statformat=json sleep 2>../out
  $ cat ../out
  \[\[\d+.* (re)

statprof can be used as a standalone module

  $ $PYTHON -m mercurial.statprof hotpath
  must specify --file to load
  [1]

  $ cd ..