From 30cbfe1f71fcc1d3fb3e696561373c5cf29391c2 Mon Sep 17 00:00:00 2001
From: Diptanu Choudhury <diptanuc@gmail.com>
Date: Thu, 19 May 2016 13:32:03 -0700
Subject: [PATCH] Implemented cpu stats

---
 client/driver/docker.go                  | 16 ++++++++-
 client/driver/executor/executor.go       | 11 +++++--
 client/driver/executor/executor_linux.go |  4 +++
 client/stats/cpu.go                      | 41 ++++++++++++++++++++++++
 4 files changed, 69 insertions(+), 3 deletions(-)
 create mode 100644 client/stats/cpu.go

diff --git a/client/driver/docker.go b/client/driver/docker.go
index a91c7ceda..22f3042ed 100644
--- a/client/driver/docker.go
+++ b/client/driver/docker.go
@@ -990,7 +990,21 @@ func (h *DockerHandle) monitorUsage() {
 					Swap:     s.MemoryStats.Stats.Swap,
 					MaxUsage: s.MemoryStats.MaxUsage,
 				}
-				h.resourceUsage = &cstructs.TaskResourceUsage{MemoryStats: ms, Timestamp: s.Read}
+
+				cs := &cstructs.CpuUsage{
+					SystemMode:       float64(s.CPUStats.CPUUsage.UsageInKernelmode),
+					UserMode:         float64(s.CPUStats.CPUUsage.UsageInKernelmode),
+					ThrottledPeriods: s.CPUStats.ThrottlingData.ThrottledPeriods,
+					ThrottledTime:    s.CPUStats.ThrottlingData.ThrottledTime,
+				}
+				// Calculate percentage
+				cs.Percent = 0.0
+				cpuDelta := float64(s.CPUStats.CPUUsage.TotalUsage) - float64(s.PreCPUStats.CPUUsage.TotalUsage)
+				systemDelta := float64(s.CPUStats.SystemCPUUsage) - float64(s.PreCPUStats.SystemCPUUsage)
+				if cpuDelta > 0.0 && systemDelta > 0.0 {
+					cs.Percent = (cpuDelta / systemDelta) * float64(len(s.CPUStats.CPUUsage.PercpuUsage)) * 100.0
+				}
+				h.resourceUsage = &cstructs.TaskResourceUsage{MemoryStats: ms, CpuStats: cs, Timestamp: s.Read}
 			}
 		case <-h.doneMonitoring:
 		case <-h.doneCh:
diff --git a/client/driver/executor/executor.go b/client/driver/executor/executor.go
index 9b315deab..74fdfa4a9 100644
--- a/client/driver/executor/executor.go
+++ b/client/driver/executor/executor.go
@@ -24,6 +24,7 @@ import (
 	"github.com/hashicorp/nomad/client/driver/env"
 	"github.com/hashicorp/nomad/client/driver/logging"
 	cstructs "github.com/hashicorp/nomad/client/driver/structs"
+	"github.com/hashicorp/nomad/client/stats"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
@@ -171,15 +172,22 @@ type UniversalExecutor struct {
 
 	consulService *consul.ConsulService
 	consulCtx     *ConsulContext
+	cpuStats      *stats.CpuStats
 	logger        *log.Logger
 }
 
 // NewExecutor returns an Executor
 func NewExecutor(logger *log.Logger) Executor {
-	return &UniversalExecutor{
+	exec := &UniversalExecutor{
 		logger:        logger,
 		processExited: make(chan interface{}),
 	}
+
+	if cpuStats, err := stats.NewCpuStats(); err == nil {
+		exec.cpuStats = cpuStats
+	}
+
+	return exec
 }
 
 // Version returns the api version of the executor
@@ -676,7 +684,6 @@ func (e *UniversalExecutor) collectPids() {
 		select {
 		case <-timer.C:
 			pids, err := e.getAllPids()
-			e.logger.Printf("DIPTANU PIDS %#v", pids)
 			timer.Reset(pidScanInterval)
 			if err != nil {
 				e.logger.Printf("[DEBUG] executor: error collecting pids: %v", err)
diff --git a/client/driver/executor/executor_linux.go b/client/driver/executor/executor_linux.go
index 513c6e2ea..2a77ad907 100644
--- a/client/driver/executor/executor_linux.go
+++ b/client/driver/executor/executor_linux.go
@@ -150,6 +150,7 @@ func (e *UniversalExecutor) Stats() (*cstructs.TaskResourceUsage, error) {
 	}
 
 	// CPU Related Stats
+	totalProcessCPUUsage := stats.CpuStats.CpuUsage.TotalUsage
 	userModeTime := stats.CpuStats.CpuUsage.UsageInUsermode
 	kernelModeTime := stats.CpuStats.CpuUsage.UsageInKernelmode
 
@@ -162,6 +163,9 @@ func (e *UniversalExecutor) Stats() (*cstructs.TaskResourceUsage, error) {
 		ThrottledPeriods: stats.CpuStats.ThrottlingData.ThrottledPeriods,
 		ThrottledTime:    stats.CpuStats.ThrottlingData.ThrottledTime,
 	}
+	if e.cpuStats != nil {
+		cs.Percent = e.cpuStats.Percent(totalProcessCPUUsage)
+	}
 	return &cstructs.TaskResourceUsage{MemoryStats: ms, CpuStats: cs, Timestamp: time.Now()}, nil
 }
 
diff --git a/client/stats/cpu.go b/client/stats/cpu.go
new file mode 100644
index 000000000..351f81dc5
--- /dev/null
+++ b/client/stats/cpu.go
@@ -0,0 +1,41 @@
+package stats
+
+import (
+	"github.com/shirou/gopsutil/cpu"
+)
+
+type CpuStats struct {
+	prevSystemUsage  float64
+	prevProcessUsage uint64
+
+	totalCpus int
+}
+
+func NewCpuStats() (*CpuStats, error) {
+	cpuInfo, err := cpu.Info()
+	if err != nil {
+		return nil, err
+	}
+	return &CpuStats{totalCpus: len(cpuInfo)}, nil
+}
+
+func (c *CpuStats) Percent(currentProcessUsage uint64) float64 {
+	percent := 0.0
+
+	sysCPUStats, err := cpu.Times(false)
+	if err != nil {
+		return 0
+	}
+	currentSysUsage := 0.0
+	for _, cpuStat := range sysCPUStats {
+		currentSysUsage += cpuStat.Total() * 1000000000
+	}
+
+	delta := float64(currentProcessUsage) - float64(c.prevProcessUsage)
+	sysDelta := float64(currentSysUsage) - float64(c.prevSystemUsage)
+
+	percent = (delta / sysDelta) * float64(c.totalCpus) * 100.0
+	c.prevSystemUsage = currentSysUsage
+	c.prevProcessUsage = currentProcessUsage
+	return percent
+}