Files
podman/vendor/github.com/tklauser/numcpus/README.md
Matt Heon d9c388e2fe Change to using gopsutil for cross-OS process ops
Instead of trying to write out own code to do basic process
operations (e.g. checking if a PID is still running in a multi-OS
friendly manner), use shirou/gopsutil, a multi-platform library
that should abstract all the complexity away. Unlike our previous
approach on Windows, this one should actually work.

Signed-off-by: Matt Heon <mheon@redhat.com>
2023-10-31 10:14:06 -04:00

53 lines
1.6 KiB
Markdown

# numcpus
[![Go Reference](https://pkg.go.dev/badge/github.com/tklauser/numcpus.svg)](https://pkg.go.dev/github.com/tklauser/numcpus)
[![GitHub Action Status](https://github.com/tklauser/numcpus/workflows/Tests/badge.svg)](https://github.com/tklauser/numcpus/actions?query=workflow%3ATests)
Package numcpus provides information about the number of CPUs in the system.
It gets the number of CPUs (online, offline, present, possible, configured or
kernel maximum) on Linux, Darwin, FreeBSD, NetBSD, OpenBSD, DragonflyBSD or
Solaris/Illumos systems.
On Linux, the information is retrieved by reading the corresponding CPU
topology files in `/sys/devices/system/cpu`.
On BSD systems, the information is retrieved using the `hw.ncpu` and
`hw.ncpuonline` sysctls, if supported.
Not all functions are supported on Darwin, FreeBSD, NetBSD, OpenBSD,
DragonflyBSD and Solaris/Illumos. ErrNotSupported is returned in case a
function is not supported on a particular platform.
## Usage
```Go
package main
import (
"fmt"
"os"
"github.com/tklauser/numcpus"
)
func main() {
online, err := numcpus.GetOnline()
if err != nil {
fmt.Fprintf(os.Stderr, "GetOnline: %v\n", err)
}
fmt.Printf("online CPUs: %v\n", online)
possible, err := numcpus.GetPossible()
if err != nil {
fmt.Fprintf(os.Stderr, "GetPossible: %v\n", err)
}
fmt.Printf("possible CPUs: %v\n", possible)
}
```
## References
* [Linux kernel sysfs documentation for CPU attributes](https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-devices-system-cpu)
* [Linux kernel CPU topology documentation](https://www.kernel.org/doc/Documentation/cputopology.txt)