Mercurial > hg
view mercurial/help/hgweb.txt @ 26379:39d643252b9f
revlog: use existing file handle when reading during _addrevision
_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.
If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.
After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.
On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:
Call Before After Delta
write 827,639 673,390 -154,249
open 700,103 684,089 -16,014
read 74,489 74,489 0
fstat 493,924 461,896 -32,028
close 249,131 233,117 -16,014
stat 242,001 242,001 0
lstat 18,676 18,676 0
lseek 20,268 20,268 0
ioctl 14,652 13,173 -1,479
TOTAL 3,180,758 2,930,679 -250,079
It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().
Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.
On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.
Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 27 Sep 2015 16:08:18 -0700 |
parents | a3f2ea1d4943 |
children | 1aee2ab0f902 |
line wrap: on
line source
Mercurial's internal web server, hgweb, can serve either a single repository, or a tree of repositories. In the second case, repository paths and global options can be defined using a dedicated configuration file common to :hg:`serve`, ``hgweb.wsgi``, ``hgweb.cgi`` and ``hgweb.fcgi``. This file uses the same syntax as other Mercurial configuration files but recognizes only the following sections: - web - paths - collections The ``web`` options are thoroughly described in :hg:`help config`. The ``paths`` section maps URL paths to paths of repositories in the filesystem. hgweb will not expose the filesystem directly - only Mercurial repositories can be published and only according to the configuration. The left hand side is the path in the URL. Note that hgweb reserves subpaths like ``rev`` or ``file``, try using different names for nested repositories to avoid confusing effects. The right hand side is the path in the filesystem. If the specified path ends with ``*`` or ``**`` the filesystem will be searched recursively for repositories below that point. With ``*`` it will not recurse into the repositories it finds (except for ``.hg/patches``). With ``**`` it will also search inside repository working directories and possibly find subrepositories. In this example:: [paths] /projects/a = /srv/tmprepos/a /projects/b = c:/repos/b / = /srv/repos/* /user/bob = /home/bob/repos/** - The first two entries make two repositories in different directories appear under the same directory in the web interface - The third entry will publish every Mercurial repository found in ``/srv/repos/``, for instance the repository ``/srv/repos/quux/`` will appear as ``http://server/quux/`` - The fourth entry will publish both ``http://server/user/bob/quux/`` and ``http://server/user/bob/quux/testsubrepo/`` The ``collections`` section is deprecated and has been superseded by ``paths``. URLs and Common Arguments ========================= URLs under each repository have the form ``/{command}[/{arguments}]`` where ``{command}`` represents the name of a command or handler and ``{arguments}`` represents any number of additional URL parameters to that command. The web server has a default style associated with it. Styles map to a collection of named templates. Each template is used to render a specific piece of data, such as a changeset or diff. The style for the current request can be overwritten two ways. First, if ``{command}`` contains a hyphen (``-``), the text before the hyphen defines the style. For example, ``/atom-log`` will render the ``log`` command handler with the ``atom`` style. The second way to set the style is with the ``style`` query string argument. For example, ``/log?style=atom``. The hyphenated URL parameter is preferred. Not all templates are available for all styles. Attempting to use a style that doesn't have all templates defined may result in an error rendering the page. Many commands take a ``{revision}`` URL parameter. This defines the changeset to operate on. This is commonly specified as the short, 12 digit hexidecimal abbreviation for the full 40 character unique revision identifier. However, any value described by :hg:`help revisions` typically works. Commands and URLs ================= The following web commands and their URLs are available: .. webcommandsmarker