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std::thread::available_parallelism: FreeBSD CPU affinity buffer increase #163286

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std::thread::available_parallelism: FreeBSD CPU affinity buffer increase #163286

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21 changes: 19 additions & 2 deletions library/std/src/sys/thread/unix.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -181,12 +181,29 @@ pub fn available_parallelism() -> io::Result<NonZero<usize>> {
{
#[cfg(not(target_os = "freebsd"))]
type Cpuset = libc::cpu_set_t;
// FreeBSD >= 13.2 having smaller mask will just leave the remaining bits to zero,
// 1024 here to match FreeBSD >= 14.x CPU_MAXSIZE
// while ABI gate is still freebsd 12 (CPU_SETSIZE is 256).
#[cfg(target_os = "freebsd")]
type Cpuset = libc::cpuset_t;
const CPU_MAXSIZE: usize = 1024;
#[cfg(target_os = "freebsd")]
type Cpuset = [libc::c_long; CPU_MAXSIZE / libc::c_long::BITS as usize];
let mut set: Cpuset = unsafe { mem::zeroed() };
unsafe {
if libc::sched_getaffinity(0, size_of::<Cpuset>(), &mut set) == 0 {
#[cfg(not(target_os = "freebsd"))]
let affinity = libc::sched_getaffinity(0, size_of::<Cpuset>(), &mut set);
#[cfg(target_os = "freebsd")]
let affinity = libc::sched_getaffinity(
0,
size_of::<Cpuset>(),
set.as_mut_ptr().cast::<libc::cpuset_t>(),
);

if affinity == 0 {
#[cfg(not(target_os = "freebsd"))]
let count = libc::CPU_COUNT(&set) as usize;
#[cfg(target_os = "freebsd")]
let count: usize = set.iter().map(|s| s.count_ones() as usize).sum();
let count = count.min(quota);

// According to sched_getaffinity's API it should always be non-zero, but
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