First attempt at collecting at least *some* perf events

Signed-off-by: Maciej "Iwan" Iwanowski <maciej.iwanowski@intel.com>

manager/container.go

@@ -91,6 +91,9 @@ type containerData struct {
 
 	// nvidiaCollector updates stats for Nvidia GPUs attached to the container.
 	nvidiaCollector stats.Collector
+
+	// perfCollector updates stats for perf_event cgroup controller.
+	perfCollector stats.Collector
 }
 
 // jitter returns a time.Duration between duration and duration + maxFactor * duration,

manager/manager.go

@@ -943,6 +943,16 @@ func (m *manager) createContainerLocked(containerName string, watchSource watche
 				klog.V(4).Infof("GPU metrics may be unavailable/incomplete for container %q: %v", cont.info.Name, err)
 			}
 		}
+
+		perfCgroupPath, err := handler.GetCgroupPath("perf_event")
+		if err != nil {
+			klog.Warningf("Error getting perf_event cgroup path: %q", err)
+		} else {
+			cont.perfCollector, err = m.perfManager.GetCollector(perfCgroupPath)
+			if err != nil {
+				klog.V(4).Infof("perf_event metrics will not be available for container %q: %q", cont.info.Name, err)
+			}
+		}
 	}
 
 	// Add collectors

perf/collector.go

@@ -15,11 +15,57 @@
 // Collector of perf events for a container.
 package perf
 
-import v1 "github.com/google/cadvisor/info/v1"
+import (
+	"fmt"
+	v1 "github.com/google/cadvisor/info/v1"
+	"golang.org/x/sys/unix"
+	"k8s.io/klog"
+	"os"
+	"unsafe"
+)
 
 type collector struct {
+	cgroupPath string
+	events     Events
+	fileDescriptors []int
 }
 
 func (c *collector) UpdateStats(stats *v1.ContainerStats) error {
-	panic("implement me")
+	klog.Infof("Attempting to update perf_event stats from cgroup %q", c.cgroupPath)
+	return nil
+}
+
+func (c *collector) setup() error {
+	for _, event := range c.events.NonGrouped {
+		klog.Infof("Setting up non-grouped perf event %#v", event)
+		length := len(event.Config)
+		size := uint32(unsafe.Sizeof(unix.PerfEventAttr{}))
+
+		config := &unix.PerfEventAttr{
+			Type:   event.Type,
+			Config: event.Config[0],
+			Size: size,
+		}
+		if length >= 2 {
+			config.Ext1 = event.Config[1]
+		}
+		if length == 3 {
+			config.Ext2 = event.Config[2]
+		}
+		klog.Infof("perf_event_attr struct prepared: %#v", config)
+
+		cgroupFd, err := os.Open(c.cgroupPath)
+		if err != nil {
+			klog.Errorf("Cannot open cgroup directory %q: %q", c.cgroupPath, err)
+			return fmt.Errorf("cannot open cgroup directory %q: %q", c.cgroupPath, err)
+		}
+		pid, cpu, groupFd, flags := int(cgroupFd.Fd()), -1, -1, unix.PERF_FLAG_PID_CGROUP
+		fd, err := unix.PerfEventOpen(config, pid, cpu, groupFd, flags)
+		if err != nil {
+			klog.Errorf("Setting up perf event %#v failed: %q", event, err)
+			return fmt.Errorf("setting up perf event %#v failed: %q", event, err)
+		}
+		c.fileDescriptors = append(c.fileDescriptors, fd)
+	}
+	return nil
 }

perf/manager.go

@@ -54,6 +54,12 @@ func (m *manager) Destroy() {
 	// Do nothing
 }
 
-func (m *manager) GetCollector(deviceCgroup string) (stats.Collector, error) {
-	return nil, nil
+func (m *manager) GetCollector(cgroupPath string) (stats.Collector, error) {
+	collector := &collector{cgroupPath: cgroupPath, events: m.events}
+	err := collector.setup()
+	if err != nil {
+		klog.Errorf("Unable to setup monitoring for perf_event cgroup %q: %q", cgroupPath, err)
+		return nil, fmt.Errorf("unable to setup monitoring for perf_event cgroup %q: %q", cgroupPath, err)
+	}
+	return collector, nil
 }