Merge branch 'develop' into main

collectors/likwidMetric.go

@@ -15,8 +15,11 @@ import (
 	"io/ioutil"
 	"math"
 	"os"
+	"os/signal"
 	"strconv"
 	"strings"
+	"sync"
+	"syscall"
 	"time"
 	"unsafe"
 
@@ -46,6 +49,15 @@ type LikwidCollectorEventsetConfig struct {
 	Metrics []LikwidCollectorMetricConfig `json:"metrics"`
 }
 
+type LikwidEventsetConfig struct {
+	internal int
+	gid      C.int
+	eorder   []*C.char
+	estr     *C.char
+	results  map[int]map[string]interface{}
+	metrics  map[int]map[string]float64
+}
+
 type LikwidCollectorConfig struct {
 	Eventsets      []LikwidCollectorEventsetConfig `json:"eventsets"`
 	Metrics        []LikwidCollectorMetricConfig   `json:"globalmetrics,omitempty"`
@@ -58,17 +70,18 @@ type LikwidCollectorConfig struct {
 
 type LikwidCollector struct {
 	metricCollector
-	cpulist   []C.int
-	cpu2tid   map[int]int
-	sock2tid  map[int]int
-	metrics   map[C.int]map[string]int
-	groups    []C.int
-	config    LikwidCollectorConfig
-	results   map[int]map[int]map[string]interface{}
-	mresults  map[int]map[int]map[string]float64
-	gmresults map[int]map[string]float64
-	basefreq  float64
-	running   bool
+	cpulist      []C.int
+	cpu2tid      map[int]int
+	sock2tid     map[int]int
+	metrics      map[C.int]map[string]int
+	groups       []C.int
+	config       LikwidCollectorConfig
+	gmresults    map[int]map[string]float64
+	basefreq     float64
+	running      bool
+	initialized  bool
+	likwidGroups map[C.int]LikwidEventsetConfig
+	lock         sync.Mutex
 }
 
 type LikwidMetric struct {
@@ -86,14 +99,53 @@ func eventsToEventStr(events map[string]string) string {
 	return strings.Join(elist, ",")
 }
 
+func genLikwidEventSet(input LikwidCollectorEventsetConfig) LikwidEventsetConfig {
+	tmplist := make([]string, 0)
+	elist := make([]*C.char, 0)
+	for k, v := range input.Events {
+		tmplist = append(tmplist, fmt.Sprintf("%s:%s", v, k))
+		c_counter := C.CString(k)
+		elist = append(elist, c_counter)
+	}
+	estr := strings.Join(tmplist, ",")
+	res := make(map[int]map[string]interface{})
+	met := make(map[int]map[string]float64)
+	for _, i := range topo.CpuList() {
+		res[i] = make(map[string]interface{})
+		for k := range input.Events {
+			res[i][k] = 0.0
+		}
+		met[i] = make(map[string]float64)
+		for _, v := range input.Metrics {
+			res[i][v.Name] = 0.0
+		}
+	}
+	return LikwidEventsetConfig{
+		gid:     -1,
+		eorder:  elist,
+		estr:    C.CString(estr),
+		results: res,
+		metrics: met,
+	}
+}
+
+func testLikwidMetricFormula(formula string, params []string) bool {
+	myparams := make(map[string]interface{})
+	for _, p := range params {
+		myparams[p] = float64(1.0)
+	}
+	_, err := agg.EvalFloat64Condition(formula, myparams)
+	return err == nil
+}
+
 func getBaseFreq() float64 {
+	files := []string{
+		"/sys/devices/system/cpu/cpu0/cpufreq/bios_limit",
+		"/sys/devices/system/cpu/cpu0/cpufreq/base_frequency",
+	}
 	var freq float64 = math.NaN()
-	C.power_init(0)
-	info := C.get_powerInfo()
-	if float64(info.baseFrequency) != 0 {
-		freq = float64(info.baseFrequency) * 1e6
-	} else {
-		buffer, err := ioutil.ReadFile("/sys/devices/system/cpu/cpu0/cpufreq/bios_limit")
+	for _, f := range files {
+		buffer, err := ioutil.ReadFile(f)
 		if err == nil {
 			data := strings.Replace(string(buffer), "\n", "", -1)
 			x, err := strconv.ParseInt(data, 0, 64)
@@ -102,12 +154,22 @@ func getBaseFreq() float64 {
 			}
 		}
 	}
+
+	if math.IsNaN(freq) {
+		C.power_init(0)
+		info := C.get_powerInfo()
+		if float64(info.baseFrequency) != 0 {
+			freq = float64(info.baseFrequency) * 1e6
+		}
+		C.power_finalize()
+	}
 	return freq
 }
 
 func (m *LikwidCollector) Init(config json.RawMessage) error {
-	var ret C.int
 	m.name = "LikwidCollector"
+	m.initialized = false
+	m.running = false
 	m.config.AccessMode = LIKWID_DEF_ACCESSMODE
 	m.config.LibraryPath = LIKWID_LIB_NAME
 	if len(config) > 0 {
@@ -140,172 +202,132 @@ func (m *LikwidCollector) Init(config json.RawMessage) error {
 		m.cpulist[i] = C.int(c)
 		m.cpu2tid[c] = i
 	}
-	m.sock2tid = make(map[int]int)
-	tmp := make([]C.int, 1)
-	for _, sid := range topo.SocketList() {
-		cstr := C.CString(fmt.Sprintf("S%d:0", sid))
-		ret = C.cpustr_to_cpulist(cstr, &tmp[0], 1)
-		if ret > 0 {
-			m.sock2tid[sid] = m.cpu2tid[int(tmp[0])]
-		}
-		C.free(unsafe.Pointer(cstr))
-	}
-	m.results = make(map[int]map[int]map[string]interface{})
-	m.mresults = make(map[int]map[int]map[string]float64)
+
+	m.likwidGroups = make(map[C.int]LikwidEventsetConfig)
+
+	// m.results = make(map[int]map[int]map[string]interface{})
+	// m.mresults = make(map[int]map[int]map[string]float64)
 	m.gmresults = make(map[int]map[string]float64)
-	cclog.ComponentDebug(m.name, "initialize LIKWID topology")
-	ret = C.topology_init()
-	if ret != 0 {
-		err := errors.New("failed to initialize LIKWID topology")
-		cclog.ComponentError(m.name, err.Error())
-		return err
-	}
-
-	switch m.config.AccessMode {
-	case "direct":
-		C.HPMmode(0)
-	case "accessdaemon":
-		if len(m.config.DaemonPath) > 0 {
-			p := os.Getenv("PATH")
-			os.Setenv("PATH", m.config.DaemonPath+":"+p)
-		}
-		C.HPMmode(1)
-	}
-
-	cclog.ComponentDebug(m.name, "initialize LIKWID perfmon module")
-	ret = C.perfmon_init(C.int(len(m.cpulist)), &m.cpulist[0])
-	if ret != 0 {
-		C.topology_finalize()
-		err := errors.New("failed to initialize LIKWID topology")
-		cclog.ComponentError(m.name, err.Error())
-		return err
+	for _, tid := range m.cpu2tid {
+		m.gmresults[tid] = make(map[string]float64)
 	}
 
 	// This is for the global metrics computation test
-	globalParams := make(map[string]interface{})
-	globalParams["time"] = float64(1.0)
-	globalParams["inverseClock"] = float64(1.0)
-	// While adding the events, we test the metrics whether they can be computed at all
-	for i, evset := range m.config.Eventsets {
-		var gid C.int
-		var cstr *C.char
+	totalMetrics := 0
+	// Generate parameter list for the metric computing test
+	params := make([]string, 0)
+	params = append(params, "time", "inverseClock")
+	// Generate parameter list for the global metric computing test
+	globalParams := make([]string, 0)
+	globalParams = append(globalParams, "time", "inverseClock")
+	// We test the eventset metrics whether they can be computed at all
+	for _, evset := range m.config.Eventsets {
 		if len(evset.Events) > 0 {
-			estr := eventsToEventStr(evset.Events)
-			// Generate parameter list for the metric computing test
-			params := make(map[string]interface{})
-			params["time"] = float64(1.0)
-			params["inverseClock"] = float64(1.0)
+			params = params[:2]
 			for counter := range evset.Events {
-				params[counter] = float64(1.0)
+				params = append(params, counter)
 			}
 			for _, metric := range evset.Metrics {
 				// Try to evaluate the metric
-				_, err := agg.EvalFloat64Condition(metric.Calc, params)
-				if err != nil {
-					cclog.ComponentError(m.name, "Calculation for metric", metric.Name, "failed:", err.Error())
-					continue
-				}
-				// If the metric is not in the parameter list for the global metrics, add it
-				if _, ok := globalParams[metric.Name]; !ok {
-					globalParams[metric.Name] = float64(1.0)
+				if testLikwidMetricFormula(metric.Calc, params) {
+					// Add the computable metric to the parameter list for the global metrics
+					globalParams = append(globalParams, metric.Name)
+					totalMetrics++
+				} else {
+					metric.Calc = ""
 				}
 			}
-			// Now we add the list of events to likwid
-			cstr = C.CString(estr)
-			gid = C.perfmon_addEventSet(cstr)
 		} else {
 			cclog.ComponentError(m.name, "Invalid Likwid eventset config, no events given")
 			continue
 		}
-		if gid >= 0 {
-			m.groups = append(m.groups, gid)
-		}
-		C.free(unsafe.Pointer(cstr))
-		m.results[i] = make(map[int]map[string]interface{})
-		m.mresults[i] = make(map[int]map[string]float64)
-		for tid := range m.cpulist {
-			m.results[i][tid] = make(map[string]interface{})
-			m.mresults[i][tid] = make(map[string]float64)
-			if i == 0 {
-				m.gmresults[tid] = make(map[string]float64)
-			}
-		}
 	}
 	for _, metric := range m.config.Metrics {
 		// Try to evaluate the global metric
-		_, err := agg.EvalFloat64Condition(metric.Calc, globalParams)
-		if err != nil {
-			cclog.ComponentError(m.name, "Calculation for metric", metric.Name, "failed:", err.Error())
-			continue
+		if !testLikwidMetricFormula(metric.Calc, globalParams) {
+			cclog.ComponentError(m.name, "Calculation for metric", metric.Name, "failed")
+			metric.Calc = ""
+		} else {
+			totalMetrics++
 		}
 	}
 
 	// If no event set could be added, shut down LikwidCollector
-	if len(m.groups) == 0 {
-		C.perfmon_finalize()
-		C.topology_finalize()
-		err := errors.New("no LIKWID performance group initialized")
+	if totalMetrics == 0 {
+		err := errors.New("no LIKWID eventset or metric usable")
 		cclog.ComponentError(m.name, err.Error())
 		return err
 	}
-	m.basefreq = getBaseFreq()
-	cclog.ComponentDebug(m.name, "BaseFreq", m.basefreq)
 	m.init = true
 	return nil
 }
 
 // take a measurement for 'interval' seconds of event set index 'group'
-func (m *LikwidCollector) takeMeasurement(group int, interval time.Duration) error {
+func (m *LikwidCollector) takeMeasurement(evset LikwidEventsetConfig, interval time.Duration) (bool, error) {
 	var ret C.int
-	gid := m.groups[group]
-	ret = C.perfmon_setupCounters(gid)
-	if ret != 0 {
-		gctr := C.GoString(C.perfmon_getGroupName(gid))
-		err := fmt.Errorf("failed to setup performance group %d (%s)", gid, gctr)
-		return err
+	m.lock.Lock()
+	if m.initialized {
+		ret = C.perfmon_setupCounters(evset.gid)
+		if ret != 0 {
+			var err error = nil
+			var skip bool = false
+			if ret == -37 {
+				skip = true
+			} else {
+				err = fmt.Errorf("failed to setup performance group %d", evset.gid)
+			}
+			m.lock.Unlock()
+			return skip, err
+		}
+		ret = C.perfmon_startCounters()
+		if ret != 0 {
+			var err error = nil
+			var skip bool = false
+			if ret == -37 {
+				skip = true
+			} else {
+				err = fmt.Errorf("failed to setup performance group %d", evset.gid)
+			}
+			m.lock.Unlock()
+			return skip, err
+		}
+		m.running = true
+		time.Sleep(interval)
+		m.running = false
+		ret = C.perfmon_stopCounters()
+		if ret != 0 {
+			var err error = nil
+			var skip bool = false
+			if ret == -37 {
+				skip = true
+			} else {
+				err = fmt.Errorf("failed to setup performance group %d", evset.gid)
+			}
+			m.lock.Unlock()
+			return skip, err
+		}
 	}
-	ret = C.perfmon_startCounters()
-	if ret != 0 {
-		gctr := C.GoString(C.perfmon_getGroupName(gid))
-		err := fmt.Errorf("failed to start performance group %d (%s)", gid, gctr)
-		return err
-	}
-	m.running = true
-	time.Sleep(interval)
-	m.running = false
-	ret = C.perfmon_stopCounters()
-	if ret != 0 {
-		gctr := C.GoString(C.perfmon_getGroupName(gid))
-		err := fmt.Errorf("failed to stop performance group %d (%s)", gid, gctr)
-		return err
-	}
-	return nil
+	m.lock.Unlock()
+	return false, nil
 }
 
 // Get all measurement results for an event set, derive the metric values out of the measurement results and send it
-func (m *LikwidCollector) calcEventsetMetrics(group int, interval time.Duration, output chan lp.CCMetric) error {
-	var eidx C.int
-	evset := m.config.Eventsets[group]
-	gid := m.groups[group]
+func (m *LikwidCollector) calcEventsetMetrics(evset LikwidEventsetConfig, interval time.Duration, output chan lp.CCMetric) error {
 	invClock := float64(1.0 / m.basefreq)
 
 	// Go over events and get the results
-	for eidx = 0; int(eidx) < len(evset.Events); eidx++ {
-		ctr := C.perfmon_getCounterName(gid, eidx)
-		gctr := C.GoString(ctr)
-
+	for eidx, counter := range evset.eorder {
+		gctr := C.GoString(counter)
 		for _, tid := range m.cpu2tid {
-			if tid >= 0 {
-				m.results[group][tid]["time"] = interval.Seconds()
-				m.results[group][tid]["inverseClock"] = invClock
-				res := C.perfmon_getLastResult(gid, eidx, C.int(tid))
-				m.results[group][tid][gctr] = float64(res)
-			}
+			res := C.perfmon_getLastResult(evset.gid, C.int(eidx), C.int(tid))
+			evset.results[tid][gctr] = float64(res)
+			evset.results[tid]["time"] = interval.Seconds()
+			evset.results[tid]["inverseClock"] = invClock
 		}
 	}
 
 	// Go over the event set metrics, derive the value out of the event:counter values and send it
-	for _, metric := range evset.Metrics {
+	for _, metric := range m.config.Eventsets[evset.internal].Metrics {
 		// The metric scope is determined in the Init() function
 		// Get the map scope-id -> tids
 		scopemap := m.cpu2tid
@@ -313,13 +335,13 @@ func (m *LikwidCollector) calcEventsetMetrics(group int, interval time.Duration,
 			scopemap = m.sock2tid
 		}
 		for domain, tid := range scopemap {
-			if tid >= 0 {
-				value, err := agg.EvalFloat64Condition(metric.Calc, m.results[group][tid])
+			if tid >= 0 && len(metric.Calc) > 0 {
+				value, err := agg.EvalFloat64Condition(metric.Calc, evset.results[tid])
 				if err != nil {
 					cclog.ComponentError(m.name, "Calculation for metric", metric.Name, "failed:", err.Error())
 					continue
 				}
-				m.mresults[group][tid][metric.Name] = value
+				evset.metrics[tid][metric.Name] = value
 				if m.config.InvalidToZero && math.IsNaN(value) {
 					value = 0.0
 				}
@@ -360,8 +382,8 @@ func (m *LikwidCollector) calcGlobalMetrics(interval time.Duration, output chan
 			if tid >= 0 {
 				// Here we generate parameter list
 				params := make(map[string]interface{})
-				for j := range m.groups {
-					for mname, mres := range m.mresults[j][tid] {
+				for _, evset := range m.likwidGroups {
+					for mname, mres := range evset.metrics[tid] {
 						params[mname] = mres
 					}
 				}
@@ -401,38 +423,145 @@ func (m *LikwidCollector) calcGlobalMetrics(interval time.Duration, output chan
 	return nil
 }
 
+func (m *LikwidCollector) LateInit() error {
+	var ret C.int
+	switch m.config.AccessMode {
+	case "direct":
+		C.HPMmode(0)
+	case "accessdaemon":
+		if len(m.config.DaemonPath) > 0 {
+			p := os.Getenv("PATH")
+			os.Setenv("PATH", m.config.DaemonPath+":"+p)
+		}
+		C.HPMmode(1)
+	}
+	cclog.ComponentDebug(m.name, "initialize LIKWID topology")
+	ret = C.topology_init()
+	if ret != 0 {
+		err := errors.New("failed to initialize LIKWID topology")
+		cclog.ComponentError(m.name, err.Error())
+		return err
+	}
+
+	m.sock2tid = make(map[int]int)
+	tmp := make([]C.int, 1)
+	for _, sid := range topo.SocketList() {
+		cstr := C.CString(fmt.Sprintf("S%d:0", sid))
+		ret = C.cpustr_to_cpulist(cstr, &tmp[0], 1)
+		if ret > 0 {
+			m.sock2tid[sid] = m.cpu2tid[int(tmp[0])]
+		}
+		C.free(unsafe.Pointer(cstr))
+	}
+
+	m.basefreq = getBaseFreq()
+	cclog.ComponentDebug(m.name, "BaseFreq", m.basefreq)
+
+	cclog.ComponentDebug(m.name, "initialize LIKWID perfmon module")
+	ret = C.perfmon_init(C.int(len(m.cpulist)), &m.cpulist[0])
+	if ret != 0 {
+		var err error = nil
+		C.topology_finalize()
+		if ret != -22 {
+			err = errors.New("failed to initialize LIKWID perfmon")
+			cclog.ComponentError(m.name, err.Error())
+		} else {
+			err = errors.New("access to LIKWID perfmon locked")
+		}
+		return err
+	}
+
+	// While adding the events, we test the metrics whether they can be computed at all
+	for i, evset := range m.config.Eventsets {
+		var gid C.int
+		if len(evset.Events) > 0 {
+			likwidGroup := genLikwidEventSet(evset)
+			// Now we add the list of events to likwid
+			gid = C.perfmon_addEventSet(likwidGroup.estr)
+			if gid >= 0 {
+				likwidGroup.gid = gid
+				likwidGroup.internal = i
+				m.likwidGroups[gid] = likwidGroup
+			}
+		} else {
+			cclog.ComponentError(m.name, "Invalid Likwid eventset config, no events given")
+			continue
+		}
+
+	}
+
+	// If no event set could be added, shut down LikwidCollector
+	if len(m.likwidGroups) == 0 {
+		C.perfmon_finalize()
+		C.topology_finalize()
+		err := errors.New("no LIKWID performance group initialized")
+		cclog.ComponentError(m.name, err.Error())
+		return err
+	}
+	sigchan := make(chan os.Signal, 1)
+	signal.Notify(sigchan, syscall.SIGCHLD)
+	signal.Notify(sigchan, os.Interrupt)
+	go func() {
+		<-sigchan
+
+		signal.Stop(sigchan)
+		m.initialized = false
+	}()
+	m.initialized = true
+	return nil
+}
+
 // main read function taking multiple measurement rounds, each 'interval' seconds long
 func (m *LikwidCollector) Read(interval time.Duration, output chan lp.CCMetric) {
+	var skip bool = false
+	var err error
 	if !m.init {
 		return
 	}
 
-	for i := range m.groups {
-		// measure event set 'i' for 'interval' seconds
-		err := m.takeMeasurement(i, interval)
-		if err != nil {
-			cclog.ComponentError(m.name, err.Error())
+	if !m.initialized {
+		if m.LateInit() != nil {
 			return
 		}
-		// read measurements and derive event set metrics
-		m.calcEventsetMetrics(i, interval, output)
 	}
-	// use the event set metrics to derive the global metrics
-	m.calcGlobalMetrics(interval, output)
+
+	if m.initialized && !skip {
+		for _, evset := range m.likwidGroups {
+			if !skip {
+				// measure event set 'i' for 'interval' seconds
+				skip, err = m.takeMeasurement(evset, interval)
+				if err != nil {
+					cclog.ComponentError(m.name, err.Error())
+					return
+				}
+			}
+
+			if !skip {
+				// read measurements and derive event set metrics
+				m.calcEventsetMetrics(evset, interval, output)
+			}
+		}
+		if !skip {
+			// use the event set metrics to derive the global metrics
+			m.calcGlobalMetrics(interval, output)
+		}
+	}
 }
 
 func (m *LikwidCollector) Close() {
 	if m.init {
-		cclog.ComponentDebug(m.name, "Closing ...")
 		m.init = false
-		if m.running {
-			cclog.ComponentDebug(m.name, "Stopping counters")
-			C.perfmon_stopCounters()
+		cclog.ComponentDebug(m.name, "Closing ...")
+		m.lock.Lock()
+		if m.initialized {
+			cclog.ComponentDebug(m.name, "Finalize LIKWID perfmon module")
+			C.perfmon_finalize()
+			m.initialized = false
 		}
-		cclog.ComponentDebug(m.name, "Finalize LIKWID perfmon module")
-		C.perfmon_finalize()
+		m.lock.Unlock()
 		cclog.ComponentDebug(m.name, "Finalize LIKWID topology module")
 		C.topology_finalize()
+
 		cclog.ComponentDebug(m.name, "Closing done")
 	}
 }

collectors/nfsMetric.go

@@ -36,7 +36,7 @@ type nfsCollector struct {
 }
 
 func (m *nfsCollector) initStats() error {
-	cmd := exec.Command(m.config.Nfsstats, `-l`)
+	cmd := exec.Command(m.config.Nfsstats, `-l`, `--all`)
 	cmd.Wait()
 	buffer, err := cmd.Output()
 	if err == nil {
@@ -52,7 +52,7 @@ func (m *nfsCollector) initStats() error {
 					if err == nil {
 						x := m.data[name]
 						x.current = value
-						x.last = 0
+						x.last = value
 						m.data[name] = x
 					}
 				}
@@ -63,7 +63,7 @@ func (m *nfsCollector) initStats() error {
 }
 
 func (m *nfsCollector) updateStats() error {
-	cmd := exec.Command(m.config.Nfsstats, `-l`)
+	cmd := exec.Command(m.config.Nfsstats, `-l`, `--all`)
 	cmd.Wait()
 	buffer, err := cmd.Output()
 	if err == nil {

internal/ccTopology/ccTopology.go

@@ -169,7 +169,10 @@ func DieList() []int {
 			}
 		}
 	}
-	return dielist
+	if len(dielist) > 0 {
+		return dielist
+	}
+	return SocketList()
 }
 
 type CpuEntry struct {
@@ -261,7 +264,7 @@ func CpuData() []CpuEntry {
 	for _, c := range CpuList() {
 		clist = append(clist, CpuEntry{Cpuid: c})
 	}
-	for _, centry := range clist {
+	for i, centry := range clist {
 		centry.Socket = -1
 		centry.Numadomain = -1
 		centry.Die = -1
@@ -289,6 +292,8 @@ func CpuData() []CpuEntry {
 		// Lookup NUMA domain id
 		centry.Numadomain = getNumaDomain(base)
 
+		// Update values in output list
+		clist[i] = centry
 	}
 	return clist
 }

internal/metricRouter/README.md

@@ -8,6 +8,8 @@ The CCMetric router sits in between the collectors and the sinks and can be used
 {
     "num_cache_intervals" : 1,
     "interval_timestamp" : true,
+    "hostname_tag" : "hostname",
+    "max_forward" : 50,
     "add_tags" : [
         {
             "key" : "cluster",
@@ -55,6 +57,20 @@ The CCMetric router sits in between the collectors and the sinks and can be used
 ```
 
 There are three main options `add_tags`, `delete_tags` and `interval_timestamp`. `add_tags` and `delete_tags` are lists consisting of dicts with `key`, `value` and `if`. The `value` can be omitted in the `delete_tags` part as it only uses the `key` for removal. The `interval_timestamp` setting means that a unique timestamp is applied to all metrics traversing the router during an interval.
+
+# Processing order in the router
+
+- Add the `hostname_tag` tag (if sent by collectors or cache)
+- If `interval_timestamp == true`, change time of metrics
+- Check if metric should be dropped (`drop_metrics` and `drop_metrics_if`)
+- Add tags from `add_tags`
+- Delete tags from `del_tags`
+- Rename metric based on `rename_metrics` and store old name as `oldname` in meta information
+- Add tags from `add_tags` (if you used the new name in the `if` condition)
+- Delete tags from `del_tags` (if you used the new name in the `if` condition)
+- Send to sinks
+- Move to cache (if `num_cache_intervals > 0`)
+
 # The `interval_timestamp` option
 
 The collectors' `Read()` functions are not called simultaneously and therefore the metrics gathered in an interval can have different timestamps. If you want to avoid that and have a common timestamp (the beginning of the interval), set this option to `true` and the MetricRouter sets the time.
@@ -65,6 +81,14 @@ If the MetricRouter should buffer metrics of intervals in a MetricCache, this op
 
 A `num_cache_intervals > 0` is required to use the `interval_aggregates` option.
 
+# The `hostname_tag` option
+
+By default, the router tags metrics with the hostname for all locally created metrics. The default tag name is `hostname`, but it can be changed if your organization wants anything else
+
+# The `max_forward` option
+
+Every time the router receives a metric through any of the channels, it tries to directly read up to `max_forward` metrics from the same channel. This was done as the router thread would go to sleep and wake up with every arriving metric. The default are `50` metrics at once and `max_forward` needs to greater than `1`.
+
 # The `rename_metrics` option
 
 In the ClusterCockpit world we specified a set of standard metrics. Since some collectors determine the metric names based on files, execuables and libraries, they might change from system to system (or installation to installtion, OS to OS, ...). In order to get the common names, you can rename incoming metrics before sending them to the sink. If the metric name matches the `oldname`, it is changed to `newname`

internal/metricRouter/metricRouter.go

@@ -103,7 +103,10 @@ func (r *metricRouter) Init(ticker mct.MultiChanTicker, wg *sync.WaitGroup, rout
 		cclog.ComponentError("MetricRouter", err.Error())
 		return err
 	}
-	r.maxForward = r.config.MaxForward
+	r.maxForward = 1
+	if r.config.MaxForward > r.maxForward {
+		r.maxForward = r.config.MaxForward
+	}
 	if r.config.NumCacheIntervals > 0 {
 		r.cache, err = NewCache(r.cache_input, r.ticker, &r.cachewg, r.config.NumCacheIntervals)
 		if err != nil {