A program to start other programs using the GPU

nvidia.go

package main

// keep in mind that applications using OpenGL needs the -gl flag to be
// correctly executed with the GPU. If that doesn't work add the -w flag as I
// noticed in some applications to make it work when -gl alone was not enough.

import (
	"bytes"
	"flag"
	"fmt"
	"os"
	"os/exec"
)

var (
	gl   = flag.Bool("gl", false, "use glx")
	wait = flag.Bool("w", false, "wait for program to exit")
)

func main() {
	flag.Parse()

	if flag.NArg() < 1 {
		flag.Usage()
		os.Exit(1)
	}

	env := []string{}
	options := []string{}

	for i, v := range flag.Args() {
		if i > 0 {
			options = append(options, v)
		}
	}

	env = append(env, os.Environ()...)
	env = append(env, "__NV_PRIME_RENDER_OFFLOAD=1")
	env = append(env, "__VK_LAYER_NV_optimus=NVIDIA_only")
	env = append(env, "__NV_PRIME_RENDER_OFFLOAD_PROVIDER=NVIDIA-G0")

	if *gl {
		env = append(env, "__GLX_VENDOR_LIBRARY_NAME=nvidia")
	}

	fmt.Printf("program: %s options: %s\n", flag.Arg(0), options)

	buff := bytes.Buffer{}

	c := exec.Cmd{
		Path:   flag.Arg(0),
		Args:   options,
		Env:    env,
		Stdout: &buff,
	}

	filepath, err := exec.LookPath(c.Path)

	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to find %s\n", c.Path)
		os.Exit(1)
	}

	c.Path = filepath

	if *wait {
		err = c.Run()
	} else {
		err = c.Start()
	}

	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to run %s, reason %v\n", c.Path, err)
	}

	if *wait {
		fmt.Printf("output: %s\n", buff.String())
	}
}