diff --git a/go.mod b/go.mod
index 15e3dcc..ccc8438 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,5 @@
 module github.com/VictoriaMetrics/metrics
 
-require github.com/valyala/histogram v1.0.1
+require github.com/valyala/histogram v1.1.1
 
 go 1.12
diff --git a/go.sum b/go.sum
index 9dd64f0..3914873 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,4 @@
 github.com/valyala/fastrand v1.0.0 h1:LUKT9aKer2dVQNUi3waewTbKV+7H17kvWFNKs2ObdkI=
 github.com/valyala/fastrand v1.0.0/go.mod h1:HWqCzkrkg6QXT8V2EXWvXCoow7vLwOFN002oeRzjapQ=
-github.com/valyala/histogram v1.0.1 h1:FzA7n2Tz/wKRMejgu3PV1vw3htAklTjjuoI6z3d4KDg=
-github.com/valyala/histogram v1.0.1/go.mod h1:lQy0xA4wUz2+IUnf97SivorsJIp8FxsnRd6x25q7Mto=
+github.com/valyala/histogram v1.1.1 h1:uyye4sBNmRMkh/XBxr0FXNO8YxqgFgSxZ0ePSG3U3Uw=
+github.com/valyala/histogram v1.1.1/go.mod h1:CZAr6gK9dbD7hYx2s8WSPh0p5x5wETjC+2b3PJVtEdg=
diff --git a/vendor/github.com/valyala/fastrand/.travis.yml b/vendor/github.com/valyala/fastrand/.travis.yml
new file mode 100644
index 0000000..336ccde
--- /dev/null
+++ b/vendor/github.com/valyala/fastrand/.travis.yml
@@ -0,0 +1,16 @@
+language: go
+
+go:
+  - 1.7
+  - 1.8
+
+script:
+  # build test for supported platforms
+  - GOOS=linux go build
+  - GOOS=darwin go build
+  - GOOS=freebsd go build
+  - GOARCH=386 go build
+
+  # run tests on a standard platform
+  - go test -v ./...
+
diff --git a/vendor/github.com/valyala/fastrand/LICENSE b/vendor/github.com/valyala/fastrand/LICENSE
new file mode 100644
index 0000000..a2b05f6
--- /dev/null
+++ b/vendor/github.com/valyala/fastrand/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2017 Aliaksandr Valialkin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/valyala/fastrand/README.md b/vendor/github.com/valyala/fastrand/README.md
new file mode 100644
index 0000000..3d384c6
--- /dev/null
+++ b/vendor/github.com/valyala/fastrand/README.md
@@ -0,0 +1,76 @@
+[![Build Status](https://travis-ci.org/valyala/fastrand.svg)](https://travis-ci.org/valyala/fastrand)
+[![GoDoc](https://godoc.org/github.com/valyala/fastrand?status.svg)](http://godoc.org/github.com/valyala/fastrand)
+[![Go Report](https://goreportcard.com/badge/github.com/valyala/fastrand)](https://goreportcard.com/report/github.com/valyala/fastrand)
+
+
+# fastrand
+
+Fast pseudorandom number generator.
+
+
+# Features
+
+- Optimized for speed.
+- Performance scales on multiple CPUs.
+
+# How does it work?
+
+It abuses [sync.Pool](https://golang.org/pkg/sync/#Pool) for maintaining
+"per-CPU" pseudorandom number generators.
+
+TODO: firgure out how to use real per-CPU pseudorandom number generators.
+
+
+# Benchmark results
+
+
+```
+$ GOMAXPROCS=1 go test -bench=. github.com/valyala/fastrand
+goos: linux
+goarch: amd64
+pkg: github.com/valyala/fastrand
+BenchmarkUint32n                   	50000000	        29.7 ns/op
+BenchmarkRNGUint32n                	200000000	         6.50 ns/op
+BenchmarkRNGUint32nWithLock        	100000000	        21.5 ns/op
+BenchmarkMathRandInt31n            	50000000	        31.8 ns/op
+BenchmarkMathRandRNGInt31n         	100000000	        17.9 ns/op
+BenchmarkMathRandRNGInt31nWithLock 	50000000	        30.2 ns/op
+PASS
+ok  	github.com/valyala/fastrand	10.634s
+```
+
+```
+$ GOMAXPROCS=2 go test -bench=. github.com/valyala/fastrand
+goos: linux
+goarch: amd64
+pkg: github.com/valyala/fastrand
+BenchmarkUint32n-2                     	100000000	        17.6 ns/op
+BenchmarkRNGUint32n-2                  	500000000	         3.36 ns/op
+BenchmarkRNGUint32nWithLock-2          	50000000	        32.0 ns/op
+BenchmarkMathRandInt31n-2              	20000000	        51.2 ns/op
+BenchmarkMathRandRNGInt31n-2           	100000000	        11.0 ns/op
+BenchmarkMathRandRNGInt31nWithLock-2   	20000000	        91.0 ns/op
+PASS
+ok  	github.com/valyala/fastrand	9.543s
+```
+
+```
+$ GOMAXPROCS=4 go test -bench=. github.com/valyala/fastrand
+goos: linux
+goarch: amd64
+pkg: github.com/valyala/fastrand
+BenchmarkUint32n-4                     	100000000	        14.2 ns/op
+BenchmarkRNGUint32n-4                  	500000000	         3.30 ns/op
+BenchmarkRNGUint32nWithLock-4          	20000000	        88.7 ns/op
+BenchmarkMathRandInt31n-4              	10000000	       145 ns/op
+BenchmarkMathRandRNGInt31n-4           	200000000	         8.35 ns/op
+BenchmarkMathRandRNGInt31nWithLock-4   	20000000	       102 ns/op
+PASS
+ok  	github.com/valyala/fastrand	11.534s
+```
+
+As you can see, [fastrand.Uint32n](https://godoc.org/github.com/valyala/fastrand#Uint32n)
+scales on multiple CPUs, while [rand.Int31n](https://golang.org/pkg/math/rand/#Int31n)
+doesn't scale. Their performance is comparable on `GOMAXPROCS=1`,
+but `fastrand.Uint32n` runs 3x faster than `rand.Int31n` on `GOMAXPROCS=2`
+and 10x faster than `rand.Int31n` on `GOMAXPROCS=4`.
diff --git a/vendor/github.com/valyala/fastrand/fastrand.go b/vendor/github.com/valyala/fastrand/fastrand.go
new file mode 100644
index 0000000..3ea9177
--- /dev/null
+++ b/vendor/github.com/valyala/fastrand/fastrand.go
@@ -0,0 +1,74 @@
+// Package fastrand implements fast pesudorandom number generator
+// that should scale well on multi-CPU systems.
+//
+// Use crypto/rand instead of this package for generating
+// cryptographically secure random numbers.
+package fastrand
+
+import (
+	"sync"
+	"time"
+)
+
+// Uint32 returns pseudorandom uint32.
+//
+// It is safe calling this function from concurrent goroutines.
+func Uint32() uint32 {
+	v := rngPool.Get()
+	if v == nil {
+		v = &RNG{}
+	}
+	r := v.(*RNG)
+	x := r.Uint32()
+	rngPool.Put(r)
+	return x
+}
+
+var rngPool sync.Pool
+
+// Uint32n returns pseudorandom uint32 in the range [0..maxN).
+//
+// It is safe calling this function from concurrent goroutines.
+func Uint32n(maxN uint32) uint32 {
+	x := Uint32()
+	// See http://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
+	return uint32((uint64(x) * uint64(maxN)) >> 32)
+}
+
+// RNG is a pseudorandom number generator.
+//
+// It is unsafe to call RNG methods from concurrent goroutines.
+type RNG struct {
+	x uint32
+}
+
+// Uint32 returns pseudorandom uint32.
+//
+// It is unsafe to call this method from concurrent goroutines.
+func (r *RNG) Uint32() uint32 {
+	for r.x == 0 {
+		r.x = getRandomUint32()
+	}
+
+	// See https://en.wikipedia.org/wiki/Xorshift
+	x := r.x
+	x ^= x << 13
+	x ^= x >> 17
+	x ^= x << 5
+	r.x = x
+	return x
+}
+
+// Uint32n returns pseudorandom uint32 in the range [0..maxN).
+//
+// It is unsafe to call this method from concurrent goroutines.
+func (r *RNG) Uint32n(maxN uint32) uint32 {
+	x := r.Uint32()
+	// See http://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
+	return uint32((uint64(x) * uint64(maxN)) >> 32)
+}
+
+func getRandomUint32() uint32 {
+	x := time.Now().UnixNano()
+	return uint32((x >> 32) ^ x)
+}
diff --git a/vendor/github.com/valyala/fastrand/go.mod b/vendor/github.com/valyala/fastrand/go.mod
new file mode 100644
index 0000000..958910b
--- /dev/null
+++ b/vendor/github.com/valyala/fastrand/go.mod
@@ -0,0 +1 @@
+module github.com/valyala/fastrand
diff --git a/vendor/github.com/valyala/histogram/LICENSE b/vendor/github.com/valyala/histogram/LICENSE
new file mode 100644
index 0000000..902bcad
--- /dev/null
+++ b/vendor/github.com/valyala/histogram/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2019 Aliaksandr Valialkin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/valyala/histogram/README.md b/vendor/github.com/valyala/histogram/README.md
new file mode 100644
index 0000000..6d4eb59
--- /dev/null
+++ b/vendor/github.com/valyala/histogram/README.md
@@ -0,0 +1,9 @@
+[![GoDoc](https://godoc.org/github.com/valyala/histogram?status.svg)](http://godoc.org/github.com/valyala/histogram)
+[![Go Report](https://goreportcard.com/badge/github.com/valyala/histogram)](https://goreportcard.com/report/github.com/valyala/histogram)
+
+
+# histogram
+
+Fast histograms for Go.
+
+See [docs](https://godoc.org/github.com/valyala/histogram).
diff --git a/vendor/github.com/valyala/histogram/go.mod b/vendor/github.com/valyala/histogram/go.mod
new file mode 100644
index 0000000..984efbe
--- /dev/null
+++ b/vendor/github.com/valyala/histogram/go.mod
@@ -0,0 +1,5 @@
+module github.com/valyala/histogram
+
+go 1.12
+
+require github.com/valyala/fastrand v1.0.0
diff --git a/vendor/github.com/valyala/histogram/go.sum b/vendor/github.com/valyala/histogram/go.sum
new file mode 100644
index 0000000..2b3e848
--- /dev/null
+++ b/vendor/github.com/valyala/histogram/go.sum
@@ -0,0 +1,2 @@
+github.com/valyala/fastrand v1.0.0 h1:LUKT9aKer2dVQNUi3waewTbKV+7H17kvWFNKs2ObdkI=
+github.com/valyala/fastrand v1.0.0/go.mod h1:HWqCzkrkg6QXT8V2EXWvXCoow7vLwOFN002oeRzjapQ=
diff --git a/vendor/github.com/valyala/histogram/histogram.go b/vendor/github.com/valyala/histogram/histogram.go
new file mode 100644
index 0000000..e90dd70
--- /dev/null
+++ b/vendor/github.com/valyala/histogram/histogram.go
@@ -0,0 +1,127 @@
+// Package histogram provides building blocks for fast histograms.
+package histogram
+
+import (
+	"math"
+	"sort"
+	"sync"
+
+	"github.com/valyala/fastrand"
+)
+
+var (
+	infNeg = math.Inf(-1)
+	infPos = math.Inf(1)
+	nan    = math.NaN()
+)
+
+// Fast is a fast histogram.
+//
+// It cannot be used from concurrently running goroutines without
+// external synchronization.
+type Fast struct {
+	max   float64
+	min   float64
+	count uint64
+
+	a   []float64
+	tmp []float64
+	rng fastrand.RNG
+}
+
+// NewFast returns new fast histogram.
+func NewFast() *Fast {
+	f := &Fast{}
+	f.Reset()
+	return f
+}
+
+// Reset resets the histogram.
+func (f *Fast) Reset() {
+	f.max = infNeg
+	f.min = infPos
+	f.count = 0
+	if len(f.a) > 0 {
+		f.a = f.a[:0]
+		f.tmp = f.tmp[:0]
+	} else {
+		// Free up memory occupied by unused histogram.
+		f.a = nil
+		f.tmp = nil
+	}
+}
+
+// Update updates the f with v.
+func (f *Fast) Update(v float64) {
+	if v > f.max {
+		f.max = v
+	}
+	if v < f.min {
+		f.min = v
+	}
+
+	f.count++
+	if len(f.a) < maxSamples {
+		f.a = append(f.a, v)
+		return
+	}
+	if n := int(f.rng.Uint32n(uint32(f.count))); n < len(f.a) {
+		f.a[n] = v
+	}
+}
+
+const maxSamples = 1000
+
+// Quantile returns the quantile value for the given phi.
+func (f *Fast) Quantile(phi float64) float64 {
+	f.tmp = append(f.tmp[:0], f.a...)
+	sort.Float64s(f.tmp)
+	return f.quantile(phi)
+}
+
+// Quantiles appends quantile values to dst for the given phis.
+func (f *Fast) Quantiles(dst, phis []float64) []float64 {
+	f.tmp = append(f.tmp[:0], f.a...)
+	sort.Float64s(f.tmp)
+	for _, phi := range phis {
+		q := f.quantile(phi)
+		dst = append(dst, q)
+	}
+	return dst
+}
+
+func (f *Fast) quantile(phi float64) float64 {
+	if len(f.tmp) == 0 || math.IsNaN(phi) {
+		return nan
+	}
+	if phi <= 0 {
+		return f.min
+	}
+	if phi >= 1 {
+		return f.max
+	}
+	idx := uint(phi*float64(len(f.tmp)-1) + 0.5)
+	if idx >= uint(len(f.tmp)) {
+		idx = uint(len(f.tmp) - 1)
+	}
+	return f.tmp[idx]
+}
+
+// GetFast returns a histogram from a pool.
+func GetFast() *Fast {
+	v := fastPool.Get()
+	if v == nil {
+		return NewFast()
+	}
+	return v.(*Fast)
+}
+
+// PutFast puts hf to the pool.
+//
+// hf cannot be used after this call.
+func PutFast(f *Fast) {
+	f.Reset()
+	fastPool.Put(f)
+}
+
+var fastPool sync.Pool
diff --git a/vendor/modules.txt b/vendor/modules.txt
new file mode 100644
index 0000000..b2bed9a
--- /dev/null
+++ b/vendor/modules.txt
@@ -0,0 +1,4 @@
+# github.com/valyala/fastrand v1.0.0
+github.com/valyala/fastrand
+# github.com/valyala/histogram v1.1.1
+github.com/valyala/histogram