view tests/test-dispatch.t @ 35793:4fb2bb61597c

bundle2: increase payload part chunk size to 32kb

Bundle2 payload parts are framed chunks. Esentially, we obtain
data in equal size chunks of size `preferedchunksize` and emit those
to a generator. That generator is fed into a compressor (which can
be the no-op compressor, which just re-emits the generator). And
the output from the compressor likely goes to a file descriptor
or socket.

What this means is that small chunk sizes create more Python objects
and Python function calls than larger chunk sizes. And as we know,
Python object and function call overhead in performance sensitive
code matters (at least with CPython).

This commit increases the bundle2 part payload chunk size from 4k
to 32k. Practically speaking, this means that the chunks we feed
into a compressor (implemented in C code) or feed directly into a
file handle or socket write() are larger. It's possible the chunks
might be larger than what the receiver can handle in one logical
operation. But at that point, we're in C code, which is much more
efficient at dealing with splitting up the chunk and making multiple
function calls than Python is.

A downside to larger chunks is that the receiver has to wait for that
much data to arrive (either raw or from a decompressor) before it
can process the chunk. But 32kb still feels like a small buffer to
have to wait for. And in many cases, the client will convert from
8 read(4096) to 1 read(32768). That's happening in Python land. So
we cut down on the number of Python objects and function calls,
making the client faster as well. I don't think there are any
significant concerns to increasing the payload chunk size to 32kb.

The impact of this change on performance significant. Using `curl`
to obtain a stream clone bundle2 payload from a server on localhost
serving the mozilla-unified repository:

before: 20.78 user; 7.71 system;  80.5 MB/s
after:  13.90 user; 3.51 system; 132 MB/s
legacy:  9.72 user; 8.16 system; 132 MB/s

bundle2 stream clone generation is still more resource intensive than
legacy stream clone (that's likely because of the use of a
util.chunkbuffer). But the throughput is the same. We might
be in territory we're this is effectively a benchmark of the
networking stack or Python's syscall throughput.

From the client perspective, `hg clone -U --stream`:

before: 33.50 user; 7.95 system; 53.3 MB/s
after:  22.82 user; 7.33 system; 72.7 MB/s
legacy: 29.96 user; 7.94 system; 58.0 MB/s

And for `hg clone --stream` with a working directory update of
~230k files:

after:  119.55 user; 26.47 system; 0:57.08 wall
legacy: 126.98 user; 26.94 system; 1:05.56 wall

So, it appears that bundle2's stream clone is now definitively faster
than legacy stream clone!

Differential Revision: https://phab.mercurial-scm.org/D1932

test command parsing and dispatch

  $ hg init a
  $ cd a

Redundant options used to crash (issue436):
  $ hg -v log -v
  $ hg -v log -v x

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

Missing arg:

  $ hg cat
  hg cat: invalid arguments
  hg cat [OPTION]... FILE...
  
  output the current or given revision of files
  
  options ([+] can be repeated):
  
   -o --output FORMAT       print output to file with formatted name
   -r --rev REV             print the given revision
      --decode              apply any matching decode filter
   -I --include PATTERN [+] include names matching the given patterns
   -X --exclude PATTERN [+] exclude names matching the given patterns
  
  (use 'hg cat -h' to show more help)
  [255]

Missing parameter for early option:

  $ hg log -R 2>&1 | grep 'hg log'
  hg log: option -R requires argument
  hg log [OPTION]... [FILE]
  (use 'hg log -h' to show more help)

"--" may be an option value:

  $ hg -R -- log
  abort: repository -- not found!
  [255]
  $ hg log -R --
  abort: repository -- not found!
  [255]
  $ hg log -T --
  -- (no-eol)
  $ hg log -T -- -k nomatch

Parsing of early options should stop at "--":

  $ hg cat -- --config=hooks.pre-cat=false
  --config=hooks.pre-cat=false: no such file in rev cb9a9f314b8b
  [1]
  $ hg cat -- --debugger
  --debugger: no such file in rev cb9a9f314b8b
  [1]

Unparsable form of early options:

  $ hg cat --debugg
  abort: option --debugger may not be abbreviated!
  [255]

Parsing failure of early options should be detected before executing the
command:

  $ hg log -b '--config=hooks.pre-log=false' default
  abort: option --config may not be abbreviated!
  [255]
  $ hg log -b -R. default
  abort: option -R has to be separated from other options (e.g. not -qR) and --repository may only be abbreviated as --repo!
  [255]
  $ hg log --cwd .. -b --cwd=. default
  abort: option --cwd may not be abbreviated!
  [255]

However, we can't prevent it from loading extensions and configs:

  $ cat <<EOF > bad.py
  > raise Exception('bad')
  > EOF
  $ hg log -b '--config=extensions.bad=bad.py' default
  *** failed to import extension bad from bad.py: bad
  abort: option --config may not be abbreviated!
  [255]

  $ mkdir -p badrepo/.hg
  $ echo 'invalid-syntax' > badrepo/.hg/hgrc
  $ hg log -b -Rbadrepo default
  hg: parse error at badrepo/.hg/hgrc:1: invalid-syntax
  [255]

  $ hg log -b --cwd=inexistent default
  abort: $ENOENT$: 'inexistent'
  [255]

  $ hg log -b '--config=ui.traceback=yes' 2>&1 | grep '^Traceback'
  Traceback (most recent call last):
  $ hg log -b '--config=profiling.enabled=yes' 2>&1 | grep -i sample
  Sample count: .*|No samples recorded\. (re)

Early options can't be specified in [aliases] and [defaults] because they are
applied before the command name is resolved:

  $ hg log -b '--config=alias.log=log --config=hooks.pre-log=false'
  hg log: option -b not recognized
  error in definition for alias 'log': --config may only be given on the command
  line
  [255]

  $ hg log -b '--config=defaults.log=--config=hooks.pre-log=false'
  abort: option --config may not be abbreviated!
  [255]

Shell aliases bypass any command parsing rules but for the early one:

  $ hg log -b '--config=alias.log=!echo howdy'
  howdy

Early options must come first if HGPLAIN=+strictflags is specified:
(BUG: chg cherry-picks early options to pass them as a server command)

#if no-chg
  $ HGPLAIN=+strictflags hg log -b --config='hooks.pre-log=false' default
  abort: unknown revision '--config=hooks.pre-log=false'!
  [255]
  $ HGPLAIN=+strictflags hg log -b -R. default
  abort: unknown revision '-R.'!
  [255]
  $ HGPLAIN=+strictflags hg log -b --cwd=. default
  abort: unknown revision '--cwd=.'!
  [255]
#endif
  $ HGPLAIN=+strictflags hg log -b --debugger default
  abort: unknown revision '--debugger'!
  [255]
  $ HGPLAIN=+strictflags hg log -b --config='alias.log=!echo pwned' default
  abort: unknown revision '--config=alias.log=!echo pwned'!
  [255]

  $ HGPLAIN=+strictflags hg log --config='hooks.pre-log=false' -b default
  abort: option --config may not be abbreviated!
  [255]
  $ HGPLAIN=+strictflags hg log -q --cwd=.. -b default
  abort: option --cwd may not be abbreviated!
  [255]
  $ HGPLAIN=+strictflags hg log -q -R . -b default
  abort: option -R has to be separated from other options (e.g. not -qR) and --repository may only be abbreviated as --repo!
  [255]

  $ HGPLAIN=+strictflags hg --config='hooks.pre-log=false' log -b default
  abort: pre-log hook exited with status 1
  [255]
  $ HGPLAIN=+strictflags hg --cwd .. -q -Ra log -b default
  0:cb9a9f314b8b
  $ HGPLAIN=+strictflags hg --cwd .. -q --repository a log -b default
  0:cb9a9f314b8b
  $ HGPLAIN=+strictflags hg --cwd .. -q --repo a log -b default
  0:cb9a9f314b8b

For compatibility reasons, HGPLAIN=+strictflags is not enabled by plain HGPLAIN:

  $ HGPLAIN= hg log --config='hooks.pre-log=false' -b default
  abort: pre-log hook exited with status 1
  [255]
  $ HGPLAINEXCEPT= hg log --cwd .. -q -Ra -b default
  0:cb9a9f314b8b

[defaults]

  $ hg cat a
  a
  $ cat >> $HGRCPATH <<EOF
  > [defaults]
  > cat = -r null
  > EOF
  $ hg cat a
  a: no such file in rev 000000000000
  [1]

  $ cd "$TESTTMP"

OSError "No such file or directory" / "The system cannot find the path
specified" should include filename even when it is empty

  $ hg -R a archive ''
  abort: *: '' (glob)
  [255]

#if no-outer-repo

No repo:

  $ hg cat
  abort: no repository found in '$TESTTMP' (.hg not found)!
  [255]

#endif

#if rmcwd

Current directory removed:

  $ mkdir $TESTTMP/repo1
  $ cd $TESTTMP/repo1
  $ rm -rf $TESTTMP/repo1

The output could be one of the following and something else:
 chg: abort: failed to getcwd (errno = *) (glob)
 abort: error getting current working directory: * (glob)
 sh: 0: getcwd() failed: $ENOENT$
Since the exact behavior depends on the shell, only check it returns non-zero.
  $ HGDEMANDIMPORT=disable hg version -q 2>/dev/null || false
  [1]

#endif