3826: Move cpu stats into a function, fix interval reporting.

diff --git a/services/crunchstat/crunchstat.go b/services/crunchstat/crunchstat.go
index 0b3920c0d8b5e5903d2d1d9ec70fa619b5fe070c..bd91aa0dec752605ede06b054f8031afd25687b6 100644 (file)
--- a/services/crunchstat/crunchstat.go
+++ b/services/crunchstat/crunchstat.go
@@ -276,15 +276,48 @@ func DoNetworkStats(stderr chan<- string, cgroup Cgroup, lastSample map[string]I
        return lastSample
 }
 
+type CpuSample struct {
+       sampleTime time.Time
+       user       float64
+       sys        float64
+       cpus       int64
+}
+
+func DoCpuStats(stderr chan<- string, cgroup Cgroup, cpus int64, user_hz float64, lastSample *CpuSample) (*CpuSample) {
+       cpuacct_stat := FindStat(stderr, cgroup, "cpuacct", "cpuacct.stat")
+       if cpuacct_stat == "" {
+               return lastSample
+       }
+       b, err := OpenAndReadAll(cpuacct_stat, stderr)
+       if err != nil {
+               return lastSample
+       }
+       nextSample := &CpuSample{time.Now(), 0, 0, cpus}
+       var userTicks, sysTicks int64
+       fmt.Sscanf(string(b), "user %d\nsystem %d", &nextSample.user, &nextSample.sys)
+       nextSample.user = float64(userTicks) / user_hz
+       nextSample.sys = float64(sysTicks) / user_hz
+
+       delta := ""
+       if lastSample != nil {
+               delta = fmt.Sprintf(" -- interval %.4f seconds %.4f user %.4f sys",
+                       nextSample.sampleTime.Sub(lastSample.sampleTime).Seconds(),
+                       nextSample.user - lastSample.user,
+                       nextSample.sys - lastSample.sys)
+       }
+       stderr <- fmt.Sprintf("crunchstat: cpu %.4f user %.4f sys %d cpus%s",
+               nextSample.user, nextSample.sys, cpus, delta)
+       return nextSample
+}
+
 func PollCgroupStats(cgroup Cgroup, stderr chan string, poll int64, stop_poll_chan <-chan bool) {
-       var last_user int64 = -1
-       var last_sys int64 = -1
        var last_cpucount int64 = 0
 
        user_hz := float64(C.sysconf(C._SC_CLK_TCK))
 
        var lastNetSample map[string]IoSample = nil
        var lastDiskSample map[string]IoSample = nil
+       var lastCpuSample *CpuSample = nil
 
        poll_chan := make(chan bool, 1)
        go func() {
@@ -296,15 +329,12 @@ func PollCgroupStats(cgroup Cgroup, stderr chan string, poll int64, stop_poll_ch
                }
        }()
        for {
-               bedtime := time.Now()
                select {
                case <-stop_poll_chan:
                        return
                case <-poll_chan:
                        // Emit stats, then select again.
                }
-               morning := time.Now()
-               elapsed := morning.Sub(bedtime).Seconds()
                cpuset_cpus := FindStat(stderr, cgroup, "cpuset", "cpuset.cpus")
                if cpuset_cpus != "" {
                        b, err := OpenAndReadAll(cpuset_cpus, stderr)
@@ -325,39 +355,9 @@ func PollCgroupStats(cgroup Cgroup, stderr chan string, poll int64, stop_poll_ch
                        }
                        last_cpucount = cpus
                }
-               cpuacct_stat := FindStat(stderr, cgroup, "cpuacct", "cpuacct.stat")
-               if cpuacct_stat != "" {
-                       b, err := OpenAndReadAll(cpuacct_stat, stderr)
-                       if err != nil {
-                               // Next time around, last_user would
-                               // be >1 interval old, so stats will
-                               // be incorrect. Start over instead.
-                               last_user = -1
-
-                               // cgroup probably gone -- skip other stats too.
-                               continue
-                       }
-                       var next_user int64
-                       var next_sys int64
-                       fmt.Sscanf(string(b), "user %d\nsystem %d", &next_user, &next_sys)
-
-                       delta := ""
-                       if elapsed > 0 && last_user != -1 {
-                               delta = fmt.Sprintf(" -- interval %.4f seconds %.4f user %.4f sys",
-                                       elapsed,
-                                       float64(next_user - last_user) / user_hz,
-                                       float64(next_sys - last_sys) / user_hz)
-                       }
-                       stderr <- fmt.Sprintf("crunchstat: cpu %.4f user %.4f sys %d cpus%s",
-                               float64(next_user) / user_hz,
-                               float64(next_sys) / user_hz,
-                               last_cpucount,
-                               delta)
-                       last_user = next_user
-                       last_sys = next_sys
-               }
 
                DoMemoryStats(stderr, cgroup)
+               lastCpuSample = DoCpuStats(stderr, cgroup, last_cpucount, user_hz, lastCpuSample)
                lastDiskSample = DoBlkIoStats(stderr, cgroup, lastDiskSample)
                lastNetSample = DoNetworkStats(stderr, cgroup, lastNetSample)
        }