nvidia.go

// Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.

package main

import (
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"

	"github.com/NVIDIA/gpu-monitoring-tools/bindings/go/nvml"

	"golang.org/x/net/context"
	pluginapi "k8s.io/kubernetes/pkg/kubelet/apis/deviceplugin/v1beta1"
)

func check(err error) {
	if err != nil {
		log.Panicln("Fatal:", err)
	}
}

func generateFakeDeviceID(realID string, fakeCounter uint) string {
	return fmt.Sprintf("%s-_-%d", realID, fakeCounter)

}

func extractRealDeviceID (fakeDeviceID string) string {
	return strings.Split(fakeDeviceID, "-_-")[0]
}

func getNumberContainersPerGPU() (numGPU uint) {
	numGPU = 1 // default value
	strNum, present := os.LookupEnv(envNumberContainersPerGPU)
	if !present {
		return
	}
	rawNumGPU, err := strconv.Atoi(strNum)
	if err != nil {
		log.Panicf("Fatal: Could not parse %s environment variable: %v\n", envNumberContainersPerGPU, err)
	}
	if rawNumGPU < 1 {
		log.Panicf("Fatal: invalid %s environment variable value: %v\n", envNumberContainersPerGPU, rawNumGPU)
	}
    numGPU = uint(rawNumGPU)
	return
}

func getDevices() []*pluginapi.Device {
	n, err := nvml.GetDeviceCount()
	check(err)

	var devs []*pluginapi.Device
	log.Println("List devices")
	for j := uint(0); j < getNumberContainersPerGPU(); j++ {
		for i := uint(0); i < n; i++ {
			d, err := nvml.NewDeviceLite(i)
			check(err)
			fakeID := generateFakeDeviceID(d.UUID, j)
			log.Println("Device ID:", fakeID)
			devs = append(devs, &pluginapi.Device{
				ID:     fakeID,
				Health: pluginapi.Healthy,
			})
		}

	}

	return devs
}

func deviceExists(devs []*pluginapi.Device, id string) bool {
	for _, d := range devs {
		if d.ID == id {
			return true
		}
	}
	return false
}

func watchXIDs(ctx context.Context, devs []*pluginapi.Device, xids chan<- *pluginapi.Device) {
	eventSet := nvml.NewEventSet()
	defer nvml.DeleteEventSet(eventSet)

	for _, d := range devs {
		realDeviceID := extractRealDeviceID(d.ID)

		err := nvml.RegisterEventForDevice(eventSet, nvml.XidCriticalError, realDeviceID)
		if err != nil && strings.HasSuffix(err.Error(), "Not Supported") {
			log.Printf("Warning: %s (%s) is too old to support healthchecking: %s. Marking it unhealthy.", realDeviceID, d.ID, err)

			xids <- d
			continue
		}

		if err != nil {
			log.Panicln("Fatal:", err)
		}
	}

	for {
		select {
		case <-ctx.Done():
			return
		default:
		}

		e, err := nvml.WaitForEvent(eventSet, 5000)
		if err != nil && e.Etype != nvml.XidCriticalError {
			continue
		}

		// FIXME: formalize the full list and document it.
		// http://docs.nvidia.com/deploy/xid-errors/index.html#topic_4
		// Application errors: the GPU should still be healthy
		if e.Edata == 31 || e.Edata == 43 || e.Edata == 45 {
			continue
		}

		if e.UUID == nil || len(*e.UUID) == 0 {
			// All devices are unhealthy
			for _, d := range devs {
				xids <- d
			}
			continue
		}

		for _, d := range devs {
			if extractRealDeviceID(d.ID) == *e.UUID {
				xids <- d
			}
		}
	}
}