github.com/c0deoo1/golang1.5@v0.0.0-20220525150107-c87c805d4593/src/runtime/debug.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package runtime
     6  
     7  import "unsafe"
     8  
     9  // GOMAXPROCS sets the maximum number of CPUs that can be executing
    10  // simultaneously and returns the previous setting.  If n < 1, it does not
    11  // change the current setting.
    12  // The number of logical CPUs on the local machine can be queried with NumCPU.
    13  // This call will go away when the scheduler improves.
    14  func GOMAXPROCS(n int) int {
    15  	if n > _MaxGomaxprocs {
    16  		n = _MaxGomaxprocs
    17  	}
    18  	lock(&sched.lock)
    19  	ret := int(gomaxprocs)
    20  	unlock(&sched.lock)
    21  	if n <= 0 || n == ret {
    22  		return ret
    23  	}
    24  
    25  	stopTheWorld("GOMAXPROCS")
    26  
    27  	// newprocs will be processed by startTheWorld
    28  	newprocs = int32(n)
    29  
    30  	startTheWorld()
    31  	return ret
    32  }
    33  
    34  // NumCPU returns the number of logical CPUs usable by the current process.
    35  func NumCPU() int {
    36  	return int(ncpu)
    37  }
    38  
    39  // NumCgoCall returns the number of cgo calls made by the current process.
    40  func NumCgoCall() int64 {
    41  	var n int64
    42  	for mp := (*m)(atomicloadp(unsafe.Pointer(&allm))); mp != nil; mp = mp.alllink {
    43  		n += int64(mp.ncgocall)
    44  	}
    45  	return n
    46  }
    47  
    48  // NumGoroutine returns the number of goroutines that currently exist.
    49  func NumGoroutine() int {
    50  	return int(gcount())
    51  }