github.com/likebike/go--@v0.0.0-20190911215757-0bd925d16e96/go/src/runtime/testdata/testprog/numcpu_freebsd.go (about)

     1  // Copyright 2017 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 main
     6  
     7  import (
     8  	"bytes"
     9  	"fmt"
    10  	"os"
    11  	"os/exec"
    12  	"runtime"
    13  	"strconv"
    14  	"strings"
    15  	"syscall"
    16  )
    17  
    18  func init() {
    19  	register("FreeBSDNumCPU", FreeBSDNumCPU)
    20  	register("FreeBSDNumCPUHelper", FreeBSDNumCPUHelper)
    21  }
    22  
    23  func FreeBSDNumCPUHelper() {
    24  	fmt.Printf("%d\n", runtime.NumCPU())
    25  }
    26  
    27  func FreeBSDNumCPU() {
    28  	_, err := exec.LookPath("cpuset")
    29  	if err != nil {
    30  		// Can not test without cpuset command.
    31  		fmt.Println("OK")
    32  		return
    33  	}
    34  	_, err = exec.LookPath("sysctl")
    35  	if err != nil {
    36  		// Can not test without sysctl command.
    37  		fmt.Println("OK")
    38  		return
    39  	}
    40  	cmd := exec.Command("sysctl", "-n", "kern.smp.active")
    41  	output, err := cmd.CombinedOutput()
    42  	if err != nil {
    43  		fmt.Printf("fail to launch '%s', error: %s, output: %s\n", strings.Join(cmd.Args, " "), err, output)
    44  		return
    45  	}
    46  	if bytes.Equal(output, []byte("1\n")) == false {
    47  		// SMP mode deactivated in kernel.
    48  		fmt.Println("OK")
    49  		return
    50  	}
    51  
    52  	list, err := getList()
    53  	if err != nil {
    54  		fmt.Printf("%s\n", err)
    55  		return
    56  	}
    57  	err = checkNCPU(list)
    58  	if err != nil {
    59  		fmt.Printf("%s\n", err)
    60  		return
    61  	}
    62  	if len(list) >= 2 {
    63  		err = checkNCPU(list[:len(list)-1])
    64  		if err != nil {
    65  			fmt.Printf("%s\n", err)
    66  			return
    67  		}
    68  	}
    69  	fmt.Println("OK")
    70  	return
    71  }
    72  
    73  func getList() ([]string, error) {
    74  	pid := syscall.Getpid()
    75  
    76  	// Launch cpuset to print a list of available CPUs: pid <PID> mask: 0, 1, 2, 3.
    77  	cmd := exec.Command("cpuset", "-g", "-p", strconv.Itoa(pid))
    78  	cmdline := strings.Join(cmd.Args, " ")
    79  	output, err := cmd.CombinedOutput()
    80  	if err != nil {
    81  		return nil, fmt.Errorf("fail to execute '%s': %s", cmdline, err)
    82  	}
    83  	pos := bytes.IndexRune(output, ':')
    84  	if pos == -1 {
    85  		return nil, fmt.Errorf("invalid output from '%s', ':' not found: %s", cmdline, output)
    86  	}
    87  
    88  	var list []string
    89  	for _, val := range bytes.Split(output[pos+1:], []byte(",")) {
    90  		index := string(bytes.TrimSpace(val))
    91  		if len(index) == 0 {
    92  			continue
    93  		}
    94  		list = append(list, index)
    95  	}
    96  	if len(list) == 0 {
    97  		return nil, fmt.Errorf("empty CPU list from '%s': %s", cmdline, output)
    98  	}
    99  	return list, nil
   100  }
   101  
   102  func checkNCPU(list []string) error {
   103  	listString := strings.Join(list, ",")
   104  	if len(listString) == 0 {
   105  		return fmt.Errorf("could not check against an empty CPU list")
   106  	}
   107  
   108  	// Launch FreeBSDNumCPUHelper() with specified CPUs list.
   109  	cmd := exec.Command("cpuset", "-l", listString, os.Args[0], "FreeBSDNumCPUHelper")
   110  	cmdline := strings.Join(cmd.Args, " ")
   111  	output, err := cmd.CombinedOutput()
   112  	if err != nil {
   113  		return fmt.Errorf("fail to launch child '%s', error: %s, output: %s", cmdline, err, output)
   114  	}
   115  
   116  	// NumCPU from FreeBSDNumCPUHelper come with '\n'.
   117  	output = bytes.TrimSpace(output)
   118  	n, err := strconv.Atoi(string(output))
   119  	if err != nil {
   120  		return fmt.Errorf("fail to parse output from child '%s', error: %s, output: %s", cmdline, err, output)
   121  	}
   122  	if n != len(list) {
   123  		return fmt.Errorf("runtime.NumCPU() expected to %d, got %d when run with CPU list %s", len(list), n, listString)
   124  	}
   125  	return nil
   126  }