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Add disable_cache_oblivious feature (#51)
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When this feature is used, it will build Jemalloc with
`--disable-cache-oblivious`. The feature is disabled by default.

Signed-off-by: Carlos Galdino <cgaldino@apple.com>
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carlosgaldino authored Apr 18, 2023
1 parent 0cc7b0e commit fd00e12
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1 change: 1 addition & 0 deletions jemalloc-sys/Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@ background_threads = [ "background_threads_runtime_support" ]
stats = []
unprefixed_malloc_on_supported_platforms = []
disable_initial_exec_tls = []
disable_cache_oblivious = []

[package.metadata.docs.rs]
rustdoc-args = [ "--cfg", "jemallocator_docs" ]
7 changes: 7 additions & 0 deletions jemalloc-sys/README.md
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Expand Up @@ -84,6 +84,13 @@ This crate provides following cargo feature flags:
the error `yourlib.so: cannot allocate memory in static TLS block`, you'll
likely want to enable this.

* `disable_cache_oblivious` (disabled by default): when enabled, jemalloc is
built with the `--disable-cache-oblivious` option. In that case, all large
allocations are page-aligned as an implementation artifact. It may severely
harm CPU cache utilization. However, the cache-oblivious layout has a cost of
one extra page per large allocation which can be unfeasible for certain
applications.

### Environment variables

`jemalloc` options taking values are passed via environment variables using the
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5 changes: 5 additions & 0 deletions jemalloc-sys/build.rs
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Expand Up @@ -262,6 +262,11 @@ fn main() {
cmd.arg("--disable-initial-exec-tls");
}

if env::var("CARGO_FEATURE_DISABLE_CACHE_OBLIVIOUS").is_ok() {
info!("CARGO_FEATURE_DISABLE_CACHE_OBLIVIOUS set");
cmd.arg("--disable-cache-oblivious");
}

cmd.arg(format!("--host={}", gnu_target(&target)));
cmd.arg(format!("--build={}", gnu_target(&host)));
cmd.arg(format!("--prefix={}", out_dir.display()));
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