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Rollup merge of #85182 - CDirkx:available_concurrency, r=JohnTitor

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Move `available_concurrency` implementation to `sys`

This splits out the platform-specific implementation of `available_concurrency` to the corresponding platforms under `sys`. No changes are made to the implementation.

Tidy didn't lint against this code being originally added outside of `sys` because of a bug (see #84677), this PR also reverts the exclusion that was introduced in that bugfix.

Tracking issue of `available_concurrency`: #74479
This commit is contained in:
Yuki Okushi 2021-06-22 07:37:46 +09:00 committed by GitHub
commit 7f1a4a287f
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GPG key ID: 4AEE18F83AFDEB23
11 changed files with 182 additions and 163 deletions
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6
library/std/src/sys/hermit/thread.rs
View file

@ -1,8 +1,10 @@
#![allow(dead_code)]
use super::unsupported;
use crate::ffi::CStr;
use crate::io;
use crate::mem;
use crate::num::NonZeroUsize;
use crate::sys::hermit::abi;
use crate::sys::hermit::thread_local_dtor::run_dtors;
use crate::time::Duration;
@ -95,6 +97,10 @@ impl Thread {
}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
unsupported()
}
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> {

6
library/std/src/sys/sgx/thread.rs
View file

@ -1,6 +1,8 @@
#![cfg_attr(test, allow(dead_code))] // why is this necessary?
use super::unsupported;
use crate::ffi::CStr;
use crate::io;
use crate::num::NonZeroUsize;
use crate::time::Duration;
use super::abi::usercalls;
@ -135,6 +137,10 @@ impl Thread {
}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
unsupported()
}
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> {

83
library/std/src/sys/unix/thread.rs
View file

@ -2,6 +2,7 @@ use crate::cmp;
use crate::ffi::CStr;
use crate::io;
use crate::mem;
use crate::num::NonZeroUsize;
use crate::ptr;
use crate::sys::{os, stack_overflow};
use crate::time::Duration;
@ -198,6 +199,88 @@ impl Drop for Thread {
}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
cfg_if::cfg_if! {
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",
))] {
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"))] {
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")] {
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, Haiku, l4re
Err(io::Error::new_const(io::ErrorKind::Unsupported, &"Getting the number of hardware threads is not supported on the target platform"))
}
}
}
#[cfg(all(
not(target_os = "linux"),
not(target_os = "freebsd"),

5
library/std/src/sys/unsupported/thread.rs
View file

@ -1,6 +1,7 @@
use super::unsupported;
use crate::ffi::CStr;
use crate::io;
use crate::num::NonZeroUsize;
use crate::time::Duration;
pub struct Thread(!);
@ -30,6 +31,10 @@ impl Thread {
}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
unsupported()
}
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> {

5
library/std/src/sys/wasi/thread.rs
View file

@ -3,6 +3,7 @@
use crate::ffi::CStr;
use crate::io;
use crate::mem;
use crate::num::NonZeroUsize;
use crate::sys::unsupported;
use crate::time::Duration;
@ -63,6 +64,10 @@ impl Thread {
}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
unsupported()
}
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> {

6
library/std/src/sys/wasm/atomics/thread.rs
View file

@ -1,5 +1,7 @@
use super::unsupported;
use crate::ffi::CStr;
use crate::io;
use crate::num::NonZeroUsize;
use crate::sys::unsupported;
use crate::time::Duration;
@ -39,6 +41,10 @@ impl Thread {
pub fn join(self) {}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
unsupported()
}
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> {

18
library/std/src/sys/windows/c.rs
View file

@ -13,6 +13,7 @@ use libc::{c_void, size_t, wchar_t};
pub use self::EXCEPTION_DISPOSITION::*;
pub use self::FILE_INFO_BY_HANDLE_CLASS::*;
pub type DWORD_PTR = ULONG_PTR;
pub type DWORD = c_ulong;
pub type NonZeroDWORD = NonZero_c_ulong;
pub type HANDLE = LPVOID;
@ -53,6 +54,7 @@ pub type LPWSADATA = *mut WSADATA;
pub type LPWSAPROTOCOL_INFO = *mut WSAPROTOCOL_INFO;
pub type LPWSTR = *mut WCHAR;
pub type LPFILETIME = *mut FILETIME;
pub type LPSYSTEM_INFO = *mut SYSTEM_INFO;
pub type LPWSABUF = *mut WSABUF;
pub type LPWSAOVERLAPPED = *mut c_void;
pub type LPWSAOVERLAPPED_COMPLETION_ROUTINE = *mut c_void;
@ -533,6 +535,21 @@ pub struct FILETIME {
pub dwHighDateTime: DWORD,
}
#[repr(C)]
pub struct SYSTEM_INFO {
pub wProcessorArchitecture: WORD,
pub wReserved: WORD,
pub dwPageSize: DWORD,
pub lpMinimumApplicationAddress: LPVOID,
pub lpMaximumApplicationAddress: LPVOID,
pub dwActiveProcessorMask: DWORD_PTR,
pub dwNumberOfProcessors: DWORD,
pub dwProcessorType: DWORD,
pub dwAllocationGranularity: DWORD,
pub wProcessorLevel: WORD,
pub wProcessorRevision: WORD,
}
#[repr(C)]
pub struct OVERLAPPED {
pub Internal: *mut c_ulong,
@ -934,6 +951,7 @@ extern "system" {
pub fn GetModuleHandleW(lpModuleName: LPCWSTR) -> HMODULE;
pub fn GetSystemTimeAsFileTime(lpSystemTimeAsFileTime: LPFILETIME);
pub fn GetSystemInfo(lpSystemInfo: LPSYSTEM_INFO);
pub fn CreateEventW(
lpEventAttributes: LPSECURITY_ATTRIBUTES,

16
library/std/src/sys/windows/thread.rs
View file

@ -1,5 +1,6 @@
use crate::ffi::CStr;
use crate::io;
use crate::num::NonZeroUsize;
use crate::ptr;
use crate::sys::c;
use crate::sys::handle::Handle;
@ -98,6 +99,21 @@ impl Thread {
}
}
pub fn available_concurrency() -> io::Result<NonZeroUsize> {
let res = unsafe {
let mut sysinfo: c::SYSTEM_INFO = crate::mem::zeroed();
c::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) }),
}
}
#[cfg_attr(test, allow(dead_code))]
pub mod guard {
pub type Guard = !;

156
library/std/src/thread/available_concurrency.rs
View file

@ -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"))
}
}
}

43
library/std/src/thread/mod.rs
View file

@ -155,6 +155,7 @@ use crate::fmt;
use crate::io;
use crate::mem;
use crate::num::NonZeroU64;
use crate::num::NonZeroUsize;
use crate::panic;
use crate::panicking;
use crate::str;
@ -174,15 +175,9 @@ use crate::time::Duration;
#[macro_use]
mod local;
#[unstable(feature = "available_concurrency", issue = "74479")]
mod available_concurrency;
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::local::{AccessError, LocalKey};
#[unstable(feature = "available_concurrency", issue = "74479")]
pub use available_concurrency::available_concurrency;
// The types used by the thread_local! macro to access TLS keys. Note that there
// are two types, the "OS" type and the "fast" type. The OS thread local key
// type is accessed via platform-specific API calls and is slow, while the fast
@ -1422,3 +1417,39 @@ fn _assert_sync_and_send() {
_assert_both::<JoinHandle<()>>();
_assert_both::<Thread>();
}
/// 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> {
imp::available_concurrency()
}

1
src/tools/tidy/src/pal.rs
View file

@ -56,7 +56,6 @@ const EXCEPTION_PATHS: &[&str] = &[
"library/std/src/f32.rs",
"library/std/src/f64.rs",
"library/std/src/path.rs",
"library/std/src/thread/available_concurrency.rs",
"library/std/src/sys_common", // Should only contain abstractions over platforms
"library/std/src/net/test.rs", // Utility helpers for tests
];