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5fe476d890
The local copy of bits.OnesCount64 was added for compatibility with Go 1.8 and earlier in CL 86477. Go 1.8 is no longer supported and go.mod requires Go 1.12, so drop the local copy and use bits.OnesCount64. Change-Id: Ieb77f0cef5f8f206b74ca737449efdcfe1949d44 Reviewed-on: https://go-review.googlesource.com/c/sys/+/192357 Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
87 lines
1.9 KiB
Go
87 lines
1.9 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// CPU affinity functions
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package unix
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import (
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"math/bits"
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"unsafe"
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)
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const cpuSetSize = _CPU_SETSIZE / _NCPUBITS
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// CPUSet represents a CPU affinity mask.
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type CPUSet [cpuSetSize]cpuMask
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func schedAffinity(trap uintptr, pid int, set *CPUSet) error {
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_, _, e := RawSyscall(trap, uintptr(pid), uintptr(unsafe.Sizeof(*set)), uintptr(unsafe.Pointer(set)))
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if e != 0 {
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return errnoErr(e)
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}
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return nil
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}
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// SchedGetaffinity gets the CPU affinity mask of the thread specified by pid.
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// If pid is 0 the calling thread is used.
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func SchedGetaffinity(pid int, set *CPUSet) error {
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return schedAffinity(SYS_SCHED_GETAFFINITY, pid, set)
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}
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// SchedSetaffinity sets the CPU affinity mask of the thread specified by pid.
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// If pid is 0 the calling thread is used.
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func SchedSetaffinity(pid int, set *CPUSet) error {
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return schedAffinity(SYS_SCHED_SETAFFINITY, pid, set)
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}
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// Zero clears the set s, so that it contains no CPUs.
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func (s *CPUSet) Zero() {
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for i := range s {
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s[i] = 0
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}
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}
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func cpuBitsIndex(cpu int) int {
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return cpu / _NCPUBITS
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}
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func cpuBitsMask(cpu int) cpuMask {
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return cpuMask(1 << (uint(cpu) % _NCPUBITS))
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}
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// Set adds cpu to the set s.
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func (s *CPUSet) Set(cpu int) {
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i := cpuBitsIndex(cpu)
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if i < len(s) {
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s[i] |= cpuBitsMask(cpu)
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}
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}
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// Clear removes cpu from the set s.
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func (s *CPUSet) Clear(cpu int) {
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i := cpuBitsIndex(cpu)
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if i < len(s) {
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s[i] &^= cpuBitsMask(cpu)
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}
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}
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// IsSet reports whether cpu is in the set s.
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func (s *CPUSet) IsSet(cpu int) bool {
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i := cpuBitsIndex(cpu)
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if i < len(s) {
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return s[i]&cpuBitsMask(cpu) != 0
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}
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return false
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}
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// Count returns the number of CPUs in the set s.
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func (s *CPUSet) Count() int {
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c := 0
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for _, b := range s {
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c += bits.OnesCount64(uint64(b))
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}
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return c
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}
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