Update irqstat plugin

The plugin reports IRQ metrics to telegraf based on IRQ instead
of CPU. It now parses `/proc/softirqs` as a separate measurement.
It also collects additional metrics including IRQ type, device
and IRQ value total.

plugins/inputs/irqstat/README.md

@@ -1,22 +1,34 @@
 # Irqstat Input Plugin
 
-The irqstat plugin gathers metrics about the interrupt types and associated values for each CPU present on a system.
+The irqstat plugin gathers metrics about the interrupt types and associated values from `/proc/interrupts` and `/proc/softirqs` for each CPU present on a system.
 
 ### Configuration
 ```
 [[inputs.irqstat]]
-  include = ["0", "1"]
+  include = ["0", "1", "30", "NET_RX"]
 ```
 
 The above configuration would result in an output similar to:
 ```
 ./telegraf -config ~/irqstat_config.conf -test
 * Plugin: inputs.irqstat, Collection 1
-> irqstat,host=hostname,cpu=CPU0 1=9i,0=22i 1488751337000000000
+> interrupts,irq=30,type=PCI-MSI,device=65537-edge\ virtio1-input.0,host=hostname CPU0=1i,total=1i 1489346531000000000
+> interrupts,irq=1,host=hostname,type=IO-APIC,device=1-edge\ i8042 CPU0=9i,total=9i 1489346531000000000
+> soft_interrupts,irq=NET_RX,host=hostname CPU0=280879i,total=280879i 1489346531000000000
+> interrupts,irq=0,type=IO-APIC,device=2-edge\ timer,host=hostname CPU0=23i,total=23i 1489346531000000000
 ```
 
 # Measurements
 
-There is only one measurement reported by this plugin, `irqstat`:
-- <strong>Fields:</strong> IRQs
-- <strong>Tags:</strong> CPUs
+There are two measurements reported by this plugin.
+- `interrupts` reports metrics from the `/proc/interrupts` file
+- `soft_interrupts` reports metrics from the `/proc/softirqs` file
+
+Depending on the content of each file there will multiple tags and fields for each measurement
+- <strong>Fields:</strong>
+ - CPUx: the IRQ value based on CPU number
+ - Total: total IRQ value of all CPUs
+- <strong>Tags:</strong>
+ - IRQ: the IRQ
+ - Type: the type associated with the IRQ
+ - Device: the device associated with the IRQ

plugins/inputs/irqstat/irqstat.go

@@ -13,7 +13,6 @@ import (
 
 type Irqstat struct {
 	Include []string
-	Path    string
 	Irqmap  map[string]map[string]interface{}
 }
 
@@ -27,13 +26,10 @@ const sampleConfig = `
   ## A list of IRQs to include for metric ingestion, if not specified
   ## will default to collecting all IRQs.
   # include = ["0", "1"]
-  #
-  ## The location of the interrupts file, defaults to /proc/interrupts.
-  # path = "/some/path/interrupts"
 `
 
 func (s *Irqstat) Description() string {
-	return "This plugin gathers IRQ types and associated values from /proc/interrupts for each CPU."
+	return "This plugin gathers IRQ types and associated values from /proc/interrupts and /proc/softirqs for each CPU."
 }
 
 func (s *Irqstat) SampleConfig() string {
@@ -46,35 +42,51 @@ func (s *Irqstat) ParseIrqFile(path string) {
 	if err != nil {
 		log.Fatal(err)
 	}
-
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
+		var irqval int64
+		var irqtotal int64
+		irqdesc := "none"
+		irqdevice := "none"
 		fields := strings.Fields(scanner.Text())
 		ff := fields[0]
-
 		if ff == "CPU0" {
 			cpucount = len(fields)
 		}
 
 		if ff[len(ff)-1:] == ":" {
-			irqtype := ff[:len(ff)-1]
 			fields = fields[1:len(fields)]
+			irqtype := ff[:len(ff)-1]
+			if path == "/proc/softirqs" {
+				irqtype = irqtype + "_softirq"
+			}
+			_, err := strconv.ParseInt(irqtype, 10, 64)
+			if err == nil {
+				irqdesc = fields[cpucount]
+				irqdevice = strings.Join(fields[cpucount+1:], " ")
+			} else {
+				if len(fields) > cpucount {
+					irqdesc = strings.Join(fields[cpucount:], " ")
+				}
+			}
 			for i := 0; i < cpucount; i++ {
 				cpukey := fmt.Sprintf("CPU%d", i)
-
-				if s.Irqmap[cpukey] == nil {
-					s.Irqmap[cpukey] = make(map[string]interface{})
+				if s.Irqmap[irqtype] == nil {
+					s.Irqmap[irqtype] = make(map[string]interface{})
 				}
-
-				irqval := 0 // Default an IRQ's value to 0
+				irqval = 0
 				if i < len(fields) {
-					irqval, err = strconv.Atoi(fields[i])
+					irqval, err = strconv.ParseInt(fields[i], 10, 64)
 					if err != nil {
 						log.Fatal(err)
 					}
 				}
-				s.Irqmap[cpukey][irqtype] = irqval
+				s.Irqmap[irqtype][cpukey] = irqval
+				irqtotal = irqval + irqtotal
 			}
+			s.Irqmap[irqtype]["type"] = irqdesc
+			s.Irqmap[irqtype]["device"] = irqdevice
+			s.Irqmap[irqtype]["total"] = irqtotal
 		}
 	}
 	file.Close()
@@ -89,36 +101,44 @@ func stringInSlice(x string, list []string) bool {
 	return false
 }
 
-func (s *Irqstat) ParseIrqMap(include []string) {
-	for cpukey, irqfields := range s.Irqmap {
-		s.Irqmap[cpukey] = make(map[string]interface{})
-		for irqtype, irqval := range irqfields {
-			if stringInSlice(irqtype, include) {
-				s.Irqmap[cpukey][irqtype] = irqval
-			}
-		}
-	}
-}
-
 func (s *Irqstat) Gather(acc telegraf.Accumulator) error {
-	cputags := make(map[string]string)
-	path := s.Path
-	include := s.Include
-
-	if len(path) == 0 {
-		path = "/proc/interrupts"
-	}
-
-	if len(include) == 0 {
-		s.ParseIrqFile(path)
-	} else {
-		s.ParseIrqFile(path)
-		s.ParseIrqMap(include)
+	irqtags := make(map[string]string)
+	irqfields := make(map[string]interface{})
+	files := []string{"/proc/interrupts", "/proc/softirqs"}
+	for _, file := range files {
+		s.ParseIrqFile(file)
 	}
-
-	for cpukey, irqfields := range s.Irqmap {
-		cputags["cpu"] = cpukey
-		acc.AddFields("irqstat", irqfields, cputags)
+	for irq, fields := range s.Irqmap {
+		irqtype := strings.Split(irq, "_softirq")[0]
+		irqtags["irq"] = irqtype
+		for k, v := range fields {
+			switch t := v.(type) {
+			case int64:
+				irqfields[k] = t
+			case string:
+				irqtags[k] = t
+			}
+		}
+		for k, _ := range irqtags {
+			if irqtags[k] == "none" {
+				delete(irqtags, k)
+			}
+		}
+		if len(s.Include) == 0 {
+			if strings.HasSuffix(irq, "_softirq") {
+				acc.AddFields("soft_interrupts", irqfields, irqtags)
+			} else {
+				acc.AddFields("interrupts", irqfields, irqtags)
+			}
+		} else {
+			if stringInSlice(irqtype, s.Include) {
+				if strings.HasSuffix(irq, "_softirq") {
+					acc.AddFields("soft_interrupts", irqfields, irqtags)
+				} else {
+					acc.AddFields("interrupts", irqfields, irqtags)
+				}
+			}
+		}
 	}
 	return nil
 }