From 5d1d1a808d92440a7c0efad77fa5527e4255e596 Mon Sep 17 00:00:00 2001
From: gary rong <garyrong0905@gmail.com>
Date: Mon, 17 Sep 2018 20:32:34 +0800
Subject: [PATCH] consensus, ethdb, metrics: implement forced-meter (#17667)

---
 consensus/ethash/ethash.go |  4 ++--
 ethdb/database.go          | 15 ++++++-------
 metrics/ewma.go            |  3 ---
 metrics/meter.go           | 43 ++++++++++++++++++++++++++++++++++++--
 4 files changed, 49 insertions(+), 16 deletions(-)

diff --git a/consensus/ethash/ethash.go b/consensus/ethash/ethash.go
index b4819ca38..d124cb1e2 100644
--- a/consensus/ethash/ethash.go
+++ b/consensus/ethash/ethash.go
@@ -485,7 +485,7 @@ func New(config Config, notify []string, noverify bool) *Ethash {
 		caches:       newlru("cache", config.CachesInMem, newCache),
 		datasets:     newlru("dataset", config.DatasetsInMem, newDataset),
 		update:       make(chan struct{}),
-		hashrate:     metrics.NewMeter(),
+		hashrate:     metrics.NewMeterForced(),
 		workCh:       make(chan *sealTask),
 		fetchWorkCh:  make(chan *sealWork),
 		submitWorkCh: make(chan *mineResult),
@@ -505,7 +505,7 @@ func NewTester(notify []string, noverify bool) *Ethash {
 		caches:       newlru("cache", 1, newCache),
 		datasets:     newlru("dataset", 1, newDataset),
 		update:       make(chan struct{}),
-		hashrate:     metrics.NewMeter(),
+		hashrate:     metrics.NewMeterForced(),
 		workCh:       make(chan *sealTask),
 		fetchWorkCh:  make(chan *sealWork),
 		submitWorkCh: make(chan *mineResult),
diff --git a/ethdb/database.go b/ethdb/database.go
index 1b262b73c..99abd09b9 100644
--- a/ethdb/database.go
+++ b/ethdb/database.go
@@ -155,15 +155,12 @@ func (db *LDBDatabase) LDB() *leveldb.DB {
 
 // Meter configures the database metrics collectors and
 func (db *LDBDatabase) Meter(prefix string) {
-	if metrics.Enabled {
-		// Initialize all the metrics collector at the requested prefix
-		db.compTimeMeter = metrics.NewRegisteredMeter(prefix+"compact/time", nil)
-		db.compReadMeter = metrics.NewRegisteredMeter(prefix+"compact/input", nil)
-		db.compWriteMeter = metrics.NewRegisteredMeter(prefix+"compact/output", nil)
-		db.diskReadMeter = metrics.NewRegisteredMeter(prefix+"disk/read", nil)
-		db.diskWriteMeter = metrics.NewRegisteredMeter(prefix+"disk/write", nil)
-	}
-	// Initialize write delay metrics no matter we are in metric mode or not.
+	// Initialize all the metrics collector at the requested prefix
+	db.compTimeMeter = metrics.NewRegisteredMeter(prefix+"compact/time", nil)
+	db.compReadMeter = metrics.NewRegisteredMeter(prefix+"compact/input", nil)
+	db.compWriteMeter = metrics.NewRegisteredMeter(prefix+"compact/output", nil)
+	db.diskReadMeter = metrics.NewRegisteredMeter(prefix+"disk/read", nil)
+	db.diskWriteMeter = metrics.NewRegisteredMeter(prefix+"disk/write", nil)
 	db.writeDelayMeter = metrics.NewRegisteredMeter(prefix+"compact/writedelay/duration", nil)
 	db.writeDelayNMeter = metrics.NewRegisteredMeter(prefix+"compact/writedelay/counter", nil)
 
diff --git a/metrics/ewma.go b/metrics/ewma.go
index 3aecd4fa3..57c949e7d 100644
--- a/metrics/ewma.go
+++ b/metrics/ewma.go
@@ -17,9 +17,6 @@ type EWMA interface {
 
 // NewEWMA constructs a new EWMA with the given alpha.
 func NewEWMA(alpha float64) EWMA {
-	if !Enabled {
-		return NilEWMA{}
-	}
 	return &StandardEWMA{alpha: alpha}
 }
 
diff --git a/metrics/meter.go b/metrics/meter.go
index 82b2141a6..58d170fae 100644
--- a/metrics/meter.go
+++ b/metrics/meter.go
@@ -29,6 +29,17 @@ func GetOrRegisterMeter(name string, r Registry) Meter {
 	return r.GetOrRegister(name, NewMeter).(Meter)
 }
 
+// GetOrRegisterMeterForced returns an existing Meter or constructs and registers a
+// new StandardMeter no matter the global switch is enabled or not.
+// Be sure to unregister the meter from the registry once it is of no use to
+// allow for garbage collection.
+func GetOrRegisterMeterForced(name string, r Registry) Meter {
+	if nil == r {
+		r = DefaultRegistry
+	}
+	return r.GetOrRegister(name, NewMeterForced).(Meter)
+}
+
 // NewMeter constructs a new StandardMeter and launches a goroutine.
 // Be sure to call Stop() once the meter is of no use to allow for garbage collection.
 func NewMeter() Meter {
@@ -46,8 +57,23 @@ func NewMeter() Meter {
 	return m
 }
 
-// NewMeter constructs and registers a new StandardMeter and launches a
-// goroutine.
+// NewMeterForced constructs a new StandardMeter and launches a goroutine no matter
+// the global switch is enabled or not.
+// Be sure to call Stop() once the meter is of no use to allow for garbage collection.
+func NewMeterForced() Meter {
+	m := newStandardMeter()
+	arbiter.Lock()
+	defer arbiter.Unlock()
+	arbiter.meters[m] = struct{}{}
+	if !arbiter.started {
+		arbiter.started = true
+		go arbiter.tick()
+	}
+	return m
+}
+
+// NewRegisteredMeter constructs and registers a new StandardMeter
+// and launches a goroutine.
 // Be sure to unregister the meter from the registry once it is of no use to
 // allow for garbage collection.
 func NewRegisteredMeter(name string, r Registry) Meter {
@@ -59,6 +85,19 @@ func NewRegisteredMeter(name string, r Registry) Meter {
 	return c
 }
 
+// NewRegisteredMeterForced constructs and registers a new StandardMeter
+// and launches a goroutine no matter the global switch is enabled or not.
+// Be sure to unregister the meter from the registry once it is of no use to
+// allow for garbage collection.
+func NewRegisteredMeterForced(name string, r Registry) Meter {
+	c := NewMeterForced()
+	if nil == r {
+		r = DefaultRegistry
+	}
+	r.Register(name, c)
+	return c
+}
+
 // MeterSnapshot is a read-only copy of another Meter.
 type MeterSnapshot struct {
 	count                          int64