package metrics import ( "math" "sync" "sync/atomic" ) // EWMAs continuously calculate an exponentially-weighted moving average // based on an outside source of clock ticks. type EWMA interface { Rate() float64 Snapshot() EWMA Tick() Update(int64) } // NewEWMA constructs a new EWMA with the given alpha. func NewEWMA(alpha float64) EWMA { if !Enabled { return NilEWMA{} } return &StandardEWMA{alpha: alpha} } // NewEWMA1 constructs a new EWMA for a one-minute moving average. func NewEWMA1() EWMA { return NewEWMA(1 - math.Exp(-5.0/60.0/1)) } // NewEWMA5 constructs a new EWMA for a five-minute moving average. func NewEWMA5() EWMA { return NewEWMA(1 - math.Exp(-5.0/60.0/5)) } // NewEWMA15 constructs a new EWMA for a fifteen-minute moving average. func NewEWMA15() EWMA { return NewEWMA(1 - math.Exp(-5.0/60.0/15)) } // EWMASnapshot is a read-only copy of another EWMA. type EWMASnapshot float64 // Rate returns the rate of events per second at the time the snapshot was // taken. func (a EWMASnapshot) Rate() float64 { return float64(a) } // Snapshot returns the snapshot. func (a EWMASnapshot) Snapshot() EWMA { return a } // Tick panics. func (EWMASnapshot) Tick() { panic("Tick called on an EWMASnapshot") } // Update panics. func (EWMASnapshot) Update(int64) { panic("Update called on an EWMASnapshot") } // NilEWMA is a no-op EWMA. type NilEWMA struct{} // Rate is a no-op. func (NilEWMA) Rate() float64 { return 0.0 } // Snapshot is a no-op. func (NilEWMA) Snapshot() EWMA { return NilEWMA{} } // Tick is a no-op. func (NilEWMA) Tick() {} // Update is a no-op. func (NilEWMA) Update(n int64) {} // StandardEWMA is the standard implementation of an EWMA and tracks the number // of uncounted events and processes them on each tick. It uses the // sync/atomic package to manage uncounted events. type StandardEWMA struct { uncounted int64 // /!\ this should be the first member to ensure 64-bit alignment alpha float64 rate float64 init bool mutex sync.Mutex } // Rate returns the moving average rate of events per second. func (a *StandardEWMA) Rate() float64 { a.mutex.Lock() defer a.mutex.Unlock() return a.rate * float64(1e9) } // Snapshot returns a read-only copy of the EWMA. func (a *StandardEWMA) Snapshot() EWMA { return EWMASnapshot(a.Rate()) } // Tick ticks the clock to update the moving average. It assumes it is called // every five seconds. func (a *StandardEWMA) Tick() { count := atomic.LoadInt64(&a.uncounted) atomic.AddInt64(&a.uncounted, -count) instantRate := float64(count) / float64(5e9) a.mutex.Lock() defer a.mutex.Unlock() if a.init { a.rate += a.alpha * (instantRate - a.rate) } else { a.init = true a.rate = instantRate } } // Update adds n uncounted events. func (a *StandardEWMA) Update(n int64) { atomic.AddInt64(&a.uncounted, n) } electron4/files/serve-10.1.2'>dependabot/npm_and_yarn/devel/electron4/files/serve-10.1.2 FreeBSD GNOME current development ports (https://github.com/freebsd/freebsd-ports-gnome)
aboutsummaryrefslogtreecommitdiffstats
path: root/graphics/gthumb
Commit message (Expand)AuthorAgeFilesLines
* Cleanup LIB_DEPENDS on libpngantoine2017-12-011-1/+1
* Bump PORTREVISION for ports depending on the canonical version of GCCgerald2017-09-111-1/+1
* Revision bump of all ports with USE_GL after consolidation of mesa-libsrezny2017-05-231-1/+1
* Update to 0.6.0sunpoet2017-04-301-0/+1
* Update to 3.4.5.rakuco2017-04-232-5/+4
* Add missing implicit dependencies reported by Poudriere.rakuco2017-04-231-3/+13
* Bump PORTREVISIONs for ports depending on the canonical version of GCC andgerald2017-04-011-0/+1
* - Update gthumb to 3.4.4.1madpilot2017-01-202-8/+5
* - Update graphics/libraw to 0.18.0jhale2017-01-191-1/+1