change global allocator to jemalloc (and mimalloc on Windows) (#399)
This copies the allocator configuration used in the Ruff project. In
particular, this gives us an instant 10% win when resolving the top 1K
PyPI packages:
$ hyperfine \
"./target/profiling/puffin-dev-main resolve-many --cache-dir
cache-docker-no-build --no-build pypi_top_8k_flat.txt --limit 1000 2>
/dev/null" \
"./target/profiling/puffin-dev resolve-many --cache-dir
cache-docker-no-build --no-build pypi_top_8k_flat.txt --limit 1000 2>
/dev/null"
Benchmark 1: ./target/profiling/puffin-dev-main resolve-many --cache-dir
cache-docker-no-build --no-build pypi_top_8k_flat.txt --limit 1000 2>
/dev/null
Time (mean ± σ): 974.2 ms ± 26.4 ms [User: 17503.3 ms, System: 2205.3
ms]
Range (min … max): 943.5 ms … 1015.9 ms 10 runs
Benchmark 2: ./target/profiling/puffin-dev resolve-many --cache-dir
cache-docker-no-build --no-build pypi_top_8k_flat.txt --limit 1000 2>
/dev/null
Time (mean ± σ): 883.1 ms ± 23.3 ms [User: 14626.1 ms, System: 2542.2
ms]
Range (min … max): 849.5 ms … 916.9 ms 10 runs
Summary
'./target/profiling/puffin-dev resolve-many --cache-dir
cache-docker-no-build --no-build pypi_top_8k_flat.txt --limit 1000 2>
/dev/null' ran
1.10 ± 0.04 times faster than './target/profiling/puffin-dev-main
resolve-many --cache-dir cache-docker-no-build --no-build
pypi_top_8k_flat.txt --limit 1000 2> /dev/null'
I was moved to do this because I noticed `malloc`/`free` taking up a
fairly sizeable percentage of time during light profiling.
As is becoming a pattern, it will be easier to review this
commit-by-commit.
Ref #396 (wouldn't call this issue fixed)
-----
I did also try adding a `smallvec` optimization to the
`Version::release` field, but it didn't bare any fruit. I still think
there is more to explore since the results I observed don't quite line
up with what I expect. (So probably either my mental model is off or my
measurement process is flawed.) You can see that attempt with a little
more explanation here:
https://github.com/astral-sh/puffin/commit/f9528b4ecd1b0c260df7e8ad57b9ddc4da09d273
In the course of adding the `smallvec` optimization, I also shrunk the
`Version` fields from a `usize` to a `u32`. They should at least be a
fixed size integer since version numbers aren't used to index memory,
and I shrunk it to `u32` since it seems reasonable to assume that all
version numbers will be smaller than `2^32`.
