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
5package runtime
6
7import (
8	"runtime/internal/atomic"
9	"unsafe"
10)
11
12// GOMAXPROCS sets the maximum number of CPUs that can be executing
13// simultaneously and returns the previous setting. If n < 1, it does not
14// change the current setting.
15// The number of logical CPUs on the local machine can be queried with NumCPU.
16// This call will go away when the scheduler improves.
17func GOMAXPROCS(n int) int {
18	if GOARCH == "wasm" && n > 1 {
19		n = 1 // WebAssembly has no threads yet, so only one CPU is possible.
20	}
21
22	lock(&sched.lock)
23	ret := int(gomaxprocs)
24	unlock(&sched.lock)
25	if n <= 0 || n == ret {
26		return ret
27	}
28
29	stopTheWorld("GOMAXPROCS")
30
31	// newprocs will be processed by startTheWorld
32	newprocs = int32(n)
33
34	startTheWorld()
35	return ret
36}
37
38// NumCPU returns the number of logical CPUs usable by the current process.
39//
40// The set of available CPUs is checked by querying the operating system
41// at process startup. Changes to operating system CPU allocation after
42// process startup are not reflected.
43func NumCPU() int {
44	return int(ncpu)
45}
46
47// NumCgoCall returns the number of cgo calls made by the current process.
48func NumCgoCall() int64 {
49	var n int64
50	for mp := (*m)(atomic.Loadp(unsafe.Pointer(&allm))); mp != nil; mp = mp.alllink {
51		n += int64(mp.ncgocall)
52	}
53	return n
54}
55
56// NumGoroutine returns the number of goroutines that currently exist.
57func NumGoroutine() int {
58	waitForSystemGoroutines()
59	return int(gcount())
60}
61
62// Get field tracking information.  Only fields with a tag go:"track"
63// are tracked.  This function will add every such field that is
64// referenced to the map.  The keys in the map will be
65// PkgPath.Name.FieldName.  The value will be true for each field
66// added.
67func Fieldtrack(map[string]bool)
68
69//go:linkname debug_modinfo runtime..z2fdebug.modinfo
70func debug_modinfo() string {
71	return modinfo
72}
73
74// setmodinfo is visible to code generated by cmd/go/internal/modload.ModInfoProg.
75//go:linkname setmodinfo runtime.setmodinfo
76func setmodinfo(s string) {
77	modinfo = s
78}
79