syncthing/lib/osutil/lowprio_unix.go

35 lines
948 B
Go

// Copyright (C) 2018 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
// +build !windows,!linux android
package osutil
import (
"syscall"
"github.com/pkg/errors"
)
// SetLowPriority lowers the process CPU scheduling priority, and possibly
// I/O priority depending on the platform and OS.
func SetLowPriority() error {
// Process zero is "self", niceness value 9 is something between 0
// (default) and 19 (worst priority).
const (
pidSelf = 0
wantNiceLevel = 9
)
if cur, err := syscall.Getpriority(syscall.PRIO_PROCESS, pidSelf); err == nil && cur >= wantNiceLevel {
// We're done here.
return nil
}
err := syscall.Setpriority(syscall.PRIO_PROCESS, pidSelf, wantNiceLevel)
return errors.Wrap(err, "set niceness") // wraps nil as nil
}