##// END OF EJS Templates
upstream » mercurial-mirror
RSS

Clone from https://www.mercurial-scm.org/repo/hg-all

merge: mark file gets as not thread safe (issue5933)...
merge: mark file gets as not thread safe (issue5933) In default installs, this has the effect of disabling the thread-based worker on Windows when manifesting files in the working directory. My measurements have shown that with revlog-based repositories, Mercurial spends a lot of CPU time in revlog code resolving file data. This ends up incurring a lot of context switching across threads and slows down `hg update` operations when going from an empty working directory to the tip of the repo. On mozilla-unified (246,351 files) on an i7-6700K (4+4 CPUs): before: 487s wall after: 360s wall (equivalent to worker.enabled=false) cpus=2: 379s wall Even with only 2 threads, the thread pool is still slower. The introduction of the thread-based worker (02b36e860e0b) states that it resulted in a "~50%" speedup for `hg sparse --enable-profile` and `hg sparse --disable-profile`. This disagrees with my measurement above. I theorize a few reasons for this: 1) Removal of files from the working directory is I/O - not CPU - bound and should benefit from a thread pool (unless I/O is insanely fast and the GIL release is near instantaneous). So tests like `hg sparse --enable-profile` may exercise deletion throughput and aren't good benchmarks for worker tasks that are CPU heavy. 2) The patch was authored by someone at Facebook. The results were likely measured against a repository using remotefilelog. And I believe that revision retrieval during working directory updates with remotefilelog will often use a remote store, thus being I/O and not CPU bound. This probably resulted in an overstated performance gain. Since there appears to be a need to enable the thread-based worker with some stores, I've made the flagging of file gets as thread safe configurable. I've made it experimental because I don't want to formalize a boolean flag for this option and because this attribute is best captured against the store implementation. But we don't have a proper store API for this yet. I'd rather cross this bridge later. It is possible there are revlog-based repositories that do benefit from a thread-based worker. I didn't do very comprehensive testing. If there are, we may want to devise a more proper algorithm for whether to use the thread-based worker, including possibly config options to limit the number of threads to use. But until I see evidence that justifies complexity, simplicity wins. Differential Revision: https://phab.mercurial-scm.org/D3963
Rodrigo Damazio Bovendorp - - Load All Authors

File last commit:

r35036:b0262b25 default
r38755:be498426 default
Show More
flags.txt
104 lines | 2.8 KiB | text/plain | TextLexer
/ mercurial / help / flags.txt
History | Annotation | Raw |Copy content |Copy permalink
Most Mercurial commands accept various flags.
Flag names
==========
Flags for each command are listed in :hg:`help` for that command.
Additionally, some flags, such as --repository, are global and can be used with
any command - those are seen in :hg:`help -v`, and can be specified before or
after the command.
Every flag has at least a long name, such as --repository. Some flags may also
have a short one-letter name, such as the equivalent -R. Using the short or long
name is equivalent and has the same effect.
Flags that have a short name can also be bundled together - for instance, to
specify both --edit (short -e) and --interactive (short -i), one could use::
hg commit -ei
If any of the bundled flags takes a value (i.e. is not a boolean), it must be
last, followed by the value::
hg commit -im 'Message'
Flag types
==========
Mercurial command-line flags can be strings, numbers, booleans, or lists of
strings.
Specifying flag values
======================
The following syntaxes are allowed, assuming a flag 'flagname' with short name
'f'::
--flagname=foo
--flagname foo
-f foo
-ffoo
This syntax applies to all non-boolean flags (strings, numbers or lists).
Specifying boolean flags
========================
Boolean flags do not take a value parameter. To specify a boolean, use the flag
name to set it to true, or the same name prefixed with 'no-' to set it to
false::
hg commit --interactive
hg commit --no-interactive
Specifying list flags
=====================
List flags take multiple values. To specify them, pass the flag multiple times::
hg files --include mercurial --include tests
Setting flag defaults
=====================
In order to set a default value for a flag in an hgrc file, it is recommended to
use aliases::
[alias]
commit = commit --interactive
For more information on hgrc files, see :hg:`help config`.
Overriding flags on the command line
====================================
If the same non-list flag is specified multiple times on the command line, the
latest specification is used::
hg commit -m "Ignored value" -m "Used value"
This includes the use of aliases - e.g., if one has::
[alias]
committemp = commit -m "Ignored value"
then the following command will override that -m::
hg committemp -m "Used value"
Overriding flag defaults
========================
Every flag has a default value, and you may also set your own defaults in hgrc
as described above.
Except for list flags, defaults can be overridden on the command line simply by
specifying the flag in that location.
Hidden flags
============
Some flags are not shown in a command's help by default - specifically, those
that are deemed to be experimental, deprecated or advanced. To show all flags,
add the --verbose flag for the help command::
hg help --verbose commit