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Diffstat (limited to 'library/std/src/thread/available_concurrency.rs')
| -rw-r--r-- | library/std/src/thread/available_concurrency.rs | 156 |
1 files changed, 0 insertions, 156 deletions
diff --git a/library/std/src/thread/available_concurrency.rs b/library/std/src/thread/available_concurrency.rs deleted file mode 100644 index e8cdde88014..00000000000 --- a/library/std/src/thread/available_concurrency.rs +++ /dev/null @@ -1,156 +0,0 @@ -use crate::io; -use crate::num::NonZeroUsize; - -/// Returns the number of hardware threads available to the program. -/// -/// This value should be considered only a hint. -/// -/// # Platform-specific behavior -/// -/// If interpreted as the number of actual hardware threads, it may undercount on -/// Windows systems with more than 64 hardware threads. If interpreted as the -/// available concurrency for that process, it may overcount on Windows systems -/// when limited by a process wide affinity mask or job object limitations, and -/// it may overcount on Linux systems when limited by a process wide affinity -/// mask or affected by cgroups limits. -/// -/// # Errors -/// -/// This function will return an error in the following situations, but is not -/// limited to just these cases: -/// -/// - If the number of hardware threads is not known for the target platform. -/// - The process lacks permissions to view the number of hardware threads -/// available. -/// -/// # Examples -/// -/// ``` -/// # #![allow(dead_code)] -/// #![feature(available_concurrency)] -/// use std::thread; -/// -/// let count = thread::available_concurrency().map(|n| n.get()).unwrap_or(1); -/// ``` -#[unstable(feature = "available_concurrency", issue = "74479")] -pub fn available_concurrency() -> io::Result<NonZeroUsize> { - available_concurrency_internal() -} - -cfg_if::cfg_if! { - if #[cfg(windows)] { - #[allow(nonstandard_style)] - fn available_concurrency_internal() -> io::Result<NonZeroUsize> { - #[repr(C)] - struct SYSTEM_INFO { - wProcessorArchitecture: u16, - wReserved: u16, - dwPageSize: u32, - lpMinimumApplicationAddress: *mut u8, - lpMaximumApplicationAddress: *mut u8, - dwActiveProcessorMask: *mut u8, - dwNumberOfProcessors: u32, - dwProcessorType: u32, - dwAllocationGranularity: u32, - wProcessorLevel: u16, - wProcessorRevision: u16, - } - extern "system" { - fn GetSystemInfo(info: *mut SYSTEM_INFO) -> i32; - } - let res = unsafe { - let mut sysinfo = crate::mem::zeroed(); - GetSystemInfo(&mut sysinfo); - sysinfo.dwNumberOfProcessors as usize - }; - match res { - 0 => Err(io::Error::new_const(io::ErrorKind::NotFound, &"The number of hardware threads is not known for the target platform")), - cpus => Ok(unsafe { NonZeroUsize::new_unchecked(cpus) }), - } - } - } else if #[cfg(any( - target_os = "android", - target_os = "emscripten", - target_os = "fuchsia", - target_os = "ios", - target_os = "linux", - target_os = "macos", - target_os = "solaris", - target_os = "illumos", - ))] { - fn available_concurrency_internal() -> io::Result<NonZeroUsize> { - match unsafe { libc::sysconf(libc::_SC_NPROCESSORS_ONLN) } { - -1 => Err(io::Error::last_os_error()), - 0 => Err(io::Error::new_const(io::ErrorKind::NotFound, &"The number of hardware threads is not known for the target platform")), - cpus => Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }), - } - } - } else if #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd"))] { - fn available_concurrency_internal() -> io::Result<NonZeroUsize> { - use crate::ptr; - - let mut cpus: libc::c_uint = 0; - let mut cpus_size = crate::mem::size_of_val(&cpus); - - unsafe { - cpus = libc::sysconf(libc::_SC_NPROCESSORS_ONLN) as libc::c_uint; - } - - // Fallback approach in case of errors or no hardware threads. - if cpus < 1 { - let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0]; - let res = unsafe { - libc::sysctl( - mib.as_mut_ptr(), - 2, - &mut cpus as *mut _ as *mut _, - &mut cpus_size as *mut _ as *mut _, - ptr::null_mut(), - 0, - ) - }; - - // Handle errors if any. - if res == -1 { - return Err(io::Error::last_os_error()); - } else if cpus == 0 { - return Err(io::Error::new_const(io::ErrorKind::NotFound, &"The number of hardware threads is not known for the target platform")); - } - } - Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }) - } - } else if #[cfg(target_os = "openbsd")] { - fn available_concurrency_internal() -> io::Result<NonZeroUsize> { - use crate::ptr; - - let mut cpus: libc::c_uint = 0; - let mut cpus_size = crate::mem::size_of_val(&cpus); - let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0]; - - let res = unsafe { - libc::sysctl( - mib.as_mut_ptr(), - 2, - &mut cpus as *mut _ as *mut _, - &mut cpus_size as *mut _ as *mut _, - ptr::null_mut(), - 0, - ) - }; - - // Handle errors if any. - if res == -1 { - return Err(io::Error::last_os_error()); - } else if cpus == 0 { - return Err(io::Error::new_const(io::ErrorKind::NotFound, &"The number of hardware threads is not known for the target platform")); - } - - Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }) - } - } else { - // FIXME: implement on vxWorks, Redox, HermitCore, Haiku, l4re - fn available_concurrency_internal() -> io::Result<NonZeroUsize> { - Err(io::Error::new_const(io::ErrorKind::NotFound, &"The number of hardware threads is not known for the target platform")) - } - } -} |