moby/pkg/sysinfo/numcpu_linux.go
Tobias Klauser 4ec063fade
pkg/sysinfo: omit Getpid call in numCPU
The man page for sched_setaffinity(2) states the following about the pid
argument [1]:

> If pid is zero, then the mask of the calling thread is returned.

Thus the additional call to unix.Getpid can be omitted and pid = 0
passed to unix.SchedGetaffinity.

[1] https://man7.org/linux/man-pages/man2/sched_setaffinity.2.html#DESCRIPTION

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
2023-04-25 10:05:20 +02:00

17 lines
467 B
Go

package sysinfo // import "github.com/docker/docker/pkg/sysinfo"
import "golang.org/x/sys/unix"
// numCPU queries the system for the count of threads available
// for use to this process.
//
// Returns 0 on errors. Use |runtime.NumCPU| in that case.
func numCPU() int {
// Gets the affinity mask for a process: The very one invoking this function.
var mask unix.CPUSet
err := unix.SchedGetaffinity(0, &mask)
if err != nil {
return 0
}
return mask.Count()
}