Mercurial > hg

comparison rust/README.rst @ 44904:7ca1d635e4a6

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
rust: add a pointer for profiling to the README As figuring out how to get useful profiles is not obvious. Differential Revision: https://phab.mercurial-scm.org/D8603
author Valentin Gatien-Baron <valentin.gatienbaron@gmail.com>
date Sat, 30 May 2020 11:36:30 -0400
parents 69d3ce00df99
children e604a3c03ab9
comparison
equal deleted inserted replaced
44903:69d3ce00df99 44904:7ca1d635e4a6
31 If the environment variable ``HGWITHRUSTEXT=cpython`` is set, the Rust 31 If the environment variable ``HGWITHRUSTEXT=cpython`` is set, the Rust
32 extension will be used by default unless ``--no-rust``. 32 extension will be used by default unless ``--no-rust``.
33 33
34 One day we may use this environment variable to switch to new experimental 34 One day we may use this environment variable to switch to new experimental
35 binding crates like a hypothetical ``HGWITHRUSTEXT=hpy``. 35 binding crates like a hypothetical ``HGWITHRUSTEXT=hpy``.
36
37 Profiling
38 =========
39
40 Setting the environment variable ``RUST_LOG=trace`` will make hg print
41 a few high level rust-related performance numbers. It can also
42 indicate why the rust code cannot be used (say, using lookarounds in
43 hgignore).
44
45 ``py-spy`` (https://github.com/benfred/py-spy) can be used to
46 construct a single profile with rust functions and python functions
47 (as opposed to ``hg --profile``, which attributes time spent in rust
48 to some unlucky python code running shortly after the rust code, and
49 as opposed to tools for native code like ``perf``, which attribute
50 time to the python interpreter instead of python functions).
36 51
37 Developing Rust 52 Developing Rust
38 =============== 53 ===============
39 54
40 The current version of Rust in use is ``1.34.2``, because it's what Debian 55 The current version of Rust in use is ``1.34.2``, because it's what Debian