Mercurial > hg
view rust/README.rst @ 46018:8b0a3ff5ed12
statprof: separate functions and "line", assume 4 digit line numbers
Previously, the profile output looked like this (I've removed many lines that
are mostly inconsequential):
```
| 100.0% 0.02s hg: <module> line 43: dispatch.run()
| 100.0% 0.02s dispatch.py: run line 115: status = dispatch(req)
| 100.0% 0.02s dispatch.py: _runcatchfunc line 432: return _dispatch(req)
\ 50.0% 0.01s dispatch.py: _dispatch line 1228: return runcommand(
| 50.0% 0.01s dispatch.py: runcommand line 883: ret = _runcommand(ui, optio...
| 50.0% 0.01s dispatch.py: _runcommand line 1240: return cmdfunc()
| 50.0% 0.01s localrepo.py: __getitem__ line 1670: quick_access = self._quick_...
| 50.0% 0.01s localrepo.py: _quick_access_changeidline 1650: return self._quick_access_c...
| 50.0% 0.01s localrepo.py: __get__ line 179: return getattr(unfi, self.n...
| 50.0% 0.01s util.py: __get__ line 1747: result = self.func(obj)
| 50.0% 0.01s localrepo.py: _quick_access_changeid_wcline 1611: cl = self.unfiltered().chan...
| 50.0% 0.01s localrepo.py: __get__ line 110: return super(_basefilecache...
| 50.0% 0.01s util.py: __getattribute__line 245: self.__spec__.loader.exec_m...
| 50.0% 0.01s <frozen importlib._bootstrap_external>: exec_moduleline 783:
| 50.0% 0.01s <frozen importlib._bootstrap>: _call_with_frames_removedline 219:
| 50.0% 0.01s changelog.py: <module> line 376: class changelog(revlog.revl...
| 50.0% 0.01s util.py: __getattribute__line 245: self.__spec__.loader.exec_m...
| 50.0% 0.01s <frozen importlib._bootstrap_external>: exec_moduleline 779:
| 50.0% 0.01s <frozen importlib._bootstrap_external>: get_codeline 868:
| 50.0% 0.01s <frozen importlib._bootstrap_external>: path_statsline 1012:
| 50.0% 0.01s <frozen importlib._bootstrap_external>: _path_statline 87:
```
This has a few problems, though I'm only addressing some of them.
1. If the stuff before "line ###" is long, there's no separation between the
function name and the "line" string.
2. If the stuff before "line ###" is really long, there's excessive separation
between the "line" string and the line number.
3. We frequently have 4-digit line numbers, the code on the right wasn't
dynamically indented and ended up quite messy looking.
To solve these problems, I've added a ", " prefix before "line" iff it would
otherwise not have any separation such as spaces. I've added a 'max' so that we
never use a negative width (which is the cause of problem #2 above), and I've
added a default assumption of 4 digit line numbers (but again using a 'max' so
this shouldn't cause problems if we go beyond that.
With these changes, it now looks like this:
```
| 100.0% 0.02s hg: <module> line 43: dispatch.run()
| 100.0% 0.02s dispatch.py: run line 115: status = dispatch(req)
| 100.0% 0.02s dispatch.py: _runcatchfunc line 432: return _dispatch(req)
\ 50.0% 0.01s dispatch.py: _dispatch line 1228: return runcommand(
| 50.0% 0.01s dispatch.py: runcommand line 883: ret = _runcommand(ui, optio...
| 50.0% 0.01s dispatch.py: _runcommand line 1240: return cmdfunc()
| 50.0% 0.01s localrepo.py: __getitem__ line 1670: quick_access = self._quick_...
| 50.0% 0.01s localrepo.py: _quick_access_changeid, line 1650: return self._quick_access_c...
| 50.0% 0.01s localrepo.py: __get__ line 179: return getattr(unfi, self.n...
| 50.0% 0.01s util.py: __get__ line 1747: result = self.func(obj)
| 50.0% 0.01s localrepo.py: _quick_access_changeid_wc, line 1611: cl = self.unfiltered().chan...
| 50.0% 0.01s localrepo.py: __get__ line 110: return super(_basefilecache...
| 50.0% 0.01s util.py: __getattribute__, line 245: self.__spec__.loader.exec_m...
| 50.0% 0.01s <frozen importlib._bootstrap_external>: exec_module, line 783:
| 50.0% 0.01s <frozen importlib._bootstrap>: _call_with_frames_removed, line 219:
| 50.0% 0.01s changelog.py: <module> line 376: class changelog(revlog.revl...
| 50.0% 0.01s util.py: __getattribute__, line 245: self.__spec__.loader.exec_m...
| 50.0% 0.01s <frozen importlib._bootstrap_external>: exec_module, line 779:
| 50.0% 0.01s <frozen importlib._bootstrap_external>: get_code, line 868:
| 50.0% 0.01s <frozen importlib._bootstrap_external>: path_stats, line 1012:
| 50.0% 0.01s <frozen importlib._bootstrap_external>: _path_stat, line 87:
```
Differential Revision: https://phab.mercurial-scm.org/D9511
author | Kyle Lippincott <spectral@google.com> |
---|---|
date | Wed, 02 Dec 2020 12:33:51 -0800 |
parents | 7bd13bf99d1c |
children | ec14c37958ec |
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=================== Mercurial Rust Code =================== This directory contains various Rust code for the Mercurial project. Rust is not required to use (or build) Mercurial, but using it improves performance in some areas. There are currently three independent rust projects: - chg. An implementation of chg, in rust instead of C. - hgcli. A project that provide a (mostly) self-contained "hg" binary, for ease of deployment and a bit of speed, using PyOxidizer. See hgcli/README.md. - hg-core (and hg-cpython): implementation of some functionality of mercurial in rust, e.g. ancestry computations in revision graphs, status or pull discovery. The top-level ``Cargo.toml`` file defines a workspace containing these crates. Using Rust code =============== Local use (you need to clean previous build artifacts if you have built without rust previously):: $ make PURE=--rust local # to use ./hg $ ./tests/run-tests.py --rust # to run all tests $ ./hg debuginstall | grep -i rust # to validate rust is in use checking Rust extensions (installed) checking module policy (rust+c-allow) If the environment variable ``HGWITHRUSTEXT=cpython`` is set, the Rust extension will be used by default unless ``--no-rust``. One day we may use this environment variable to switch to new experimental binding crates like a hypothetical ``HGWITHRUSTEXT=hpy``. Special features ================ You might want to check the `features` section in ``hg-cpython/Cargo.toml``. It may contain features that might be interesting to try out. To use features from the Makefile, use the `HG_RUST_FEATURES` environment variable: for instance `HG_RUST_FEATURES="some-feature other-feature"` Profiling ========= Setting the environment variable ``RUST_LOG=trace`` will make hg print a few high level rust-related performance numbers. It can also indicate why the rust code cannot be used (say, using lookarounds in hgignore). ``py-spy`` (https://github.com/benfred/py-spy) can be used to construct a single profile with rust functions and python functions (as opposed to ``hg --profile``, which attributes time spent in rust to some unlucky python code running shortly after the rust code, and as opposed to tools for native code like ``perf``, which attribute time to the python interpreter instead of python functions). Developing Rust =============== The current version of Rust in use is ``1.41.1``, because it's what Debian stable has. You can use ``rustup override set 1.41.1`` at the root of the repo to make it easier on you. Go to the ``hg-cpython`` folder:: $ cd rust/hg-cpython Or, only the ``hg-core`` folder. Be careful not to break compatibility:: $ cd rust/hg-core Simply run:: $ cargo build --release It is possible to build without ``--release``, but it is not recommended if performance is of any interest: there can be an order of magnitude of degradation when removing ``--release``. For faster builds, you may want to skip code generation:: $ cargo check For even faster typing:: $ cargo c You can run only the rust-specific tests (as opposed to tests of mercurial as a whole) with:: $ cargo test --all Formatting the code ------------------- We use ``rustfmt`` to keep the code formatted at all times. For now, we are using the nightly version because it has been stable enough and provides comment folding. To format the entire Rust workspace:: $ cargo +nightly fmt This requires you to have the nightly toolchain installed.