streamclone: use backgroundfilecloser (issue4889)
Closing files that have been appended to is slow on Windows/NTFS.
CloseHandle() calls on this platform often take 1-10ms - and that's
on my i7-6700K Skylake processor with a modern and fast SSD. Contrast
with other I/O operations, such as writing data, which take <100us.
This means that creating/appending thousands of files can add
significant overhead. For example, cloning mozilla-central creates
~232,000 revlog files. Assuming 1ms per CloseHandle(), that yields
232s (3:52) of wall time waiting for file closes!
The impact of this overhead can be measured most directly when applying
stream clone bundles. Applying these files is effectively uncompressing
a tar archive (read: it's very fast).
Using a RAM disk (read: no I/O wait), the difference in wall time for a
`hg debugapplystreamclonebundle` for a ~1731 MB mozilla-central bundle
between Windows and Linux from the same machine is drastic:
Linux: ~12.8s (128MB/s)
Windows: ~352.0s (4.7MB/s)
Windows is ~27.5x slower. Yikes!
After this patch:
Linux: ~12.8s (128MB/s)
Windows: ~102.1s (16.1MB/s)
Windows is now ~3.4x faster. Unfortunately, it is still ~8x slower than
Linux. Profiling reveals a few hot code paths that could likely be
improved. But those are for other patches.
This patch introduces test-clone-uncompressed.t because existing tests
of `clone --uncompressed` are scattered about and adding a variation for
background thread closing to e.g. test-http.t doesn't feel correct.
from pprint import pprint
from mercurial import minirst
def debugformat(text, form, **kwargs):
if form == 'html':
print "html format:"
out = minirst.format(text, style=form, **kwargs)
else:
print "%d column format:" % form
out = minirst.format(text, width=form, **kwargs)
print "-" * 70
if type(out) == tuple:
print out[0][:-1]
print "-" * 70
pprint(out[1])
else:
print out[:-1]
print "-" * 70
print
def debugformats(title, text, **kwargs):
print "== %s ==" % title
debugformat(text, 60, **kwargs)
debugformat(text, 30, **kwargs)
debugformat(text, 'html', **kwargs)
paragraphs = """
This is some text in the first paragraph.
A small indented paragraph.
It is followed by some lines
containing random whitespace.
\n \n \nThe third and final paragraph.
"""
debugformats('paragraphs', paragraphs)
definitions = """
A Term
Definition. The indented
lines make up the definition.
Another Term
Another definition. The final line in the
definition determines the indentation, so
this will be indented with four spaces.
A Nested/Indented Term
Definition.
"""
debugformats('definitions', definitions)
literals = r"""
The fully minimized form is the most
convenient form::
Hello
literal
world
In the partially minimized form a paragraph
simply ends with space-double-colon. ::
////////////////////////////////////////
long un-wrapped line in a literal block
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
::
This literal block is started with '::',
the so-called expanded form. The paragraph
with '::' disappears in the final output.
"""
debugformats('literals', literals)
lists = """
- This is the first list item.
Second paragraph in the first list item.
- List items need not be separated
by a blank line.
- And will be rendered without
one in any case.
We can have indented lists:
- This is an indented list item
- Another indented list item::
- A literal block in the middle
of an indented list.
(The above is not a list item since we are in the literal block.)
::
Literal block with no indentation (apart from
the two spaces added to all literal blocks).
1. This is an enumerated list (first item).
2. Continuing with the second item.
(1) foo
(2) bar
1) Another
2) List
Line blocks are also a form of list:
| This is the first line.
The line continues here.
| This is the second line.
"""
debugformats('lists', lists)
options = """
There is support for simple option lists,
but only with long options:
-X, --exclude filter an option with a short and long option with an argument
-I, --include an option with both a short option and a long option
--all Output all.
--both Output both (this description is
quite long).
--long Output all day long.
--par This option has two paragraphs in its description.
This is the first.
This is the second. Blank lines may be omitted between
options (as above) or left in (as here).
The next paragraph looks like an option list, but lacks the two-space
marker after the option. It is treated as a normal paragraph:
--foo bar baz
"""
debugformats('options', options)
fields = """
:a: First item.
:ab: Second item. Indentation and wrapping
is handled automatically.
Next list:
:small: The larger key below triggers full indentation here.
:much too large: This key is big enough to get its own line.
"""
debugformats('fields', fields)
containers = """
Normal output.
.. container:: debug
Initial debug output.
.. container:: verbose
Verbose output.
.. container:: debug
Debug output.
"""
debugformats('containers (normal)', containers)
debugformats('containers (verbose)', containers, keep=['verbose'])
debugformats('containers (debug)', containers, keep=['debug'])
debugformats('containers (verbose debug)', containers,
keep=['verbose', 'debug'])
roles = """Please see :hg:`add`."""
debugformats('roles', roles)
sections = """
Title
=====
Section
-------
Subsection
''''''''''
Markup: ``foo`` and :hg:`help`
------------------------------
"""
debugformats('sections', sections)
admonitions = """
.. note::
This is a note
- Bullet 1
- Bullet 2
.. warning:: This is a warning Second
input line of warning
.. danger::
This is danger
"""
debugformats('admonitions', admonitions)
comments = """
Some text.
.. A comment
.. An indented comment
Some indented text.
..
Empty comment above
"""
debugformats('comments', comments)
data = [['a', 'b', 'c'],
['1', '2', '3'],
['foo', 'bar', 'baz this list is very very very long man']]
rst = minirst.maketable(data, 2, True)
table = ''.join(rst)
print table
debugformats('table', table)
data = [['s', 'long', 'line\ngoes on here'],
['', 'xy', 'tried to fix here\n by indenting']]
rst = minirst.maketable(data, 1, False)
table = ''.join(rst)
print table
debugformats('table+nl', table)