Computer timings on human scale – Quizz – Quizz - translate to human scale
Computer timings on human scale – Quizz – Quizz - translate to human scale
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human_scale_quizz
Taken from Erik Meijer's talk in "Principles of Reactive programming" at Coursera.orgOn Github kleibl / human_scale_quizz
Computer timings on human scale
Quizz
Taken from Erik Meijer's talk in "Principles of Reactive programming" at Coursera.org
Read and send data
trait Socket {
def readFromMemory(): Array[Byte]
def sendToEurope(packet: Array[Byte]): Array[Byte]
}
val socket = Socket()
val packet = socket.readFromMemory()
val confirmation = socket.sendToEurope(packet)
Approximate timing for various operations on a typical PC
execute typical instruction 1/1,000,000,000 sec = 1 nanosec fetch from L1 cache memory 0.5 nanosec branch misprediction 5 nanosec fetch from L2 cache memory 7 nanosec Mutex lock/unlock 25 nanosec fetch from main memory 100 nanosec send 2K bytes over 1Gbps network 20,000 nanosec read 1MB sequentially from memory 250,000 nanosec fetch from new disk location (seek) 8,000,000 nanosec read 1MB sequentially from disk 20,000,000 nanosec send packet US to Europe and back 150 milliseconds = 150,000,000 nanosecRead and send data
trait Socket {
def readFromMemory(): Array[Byte]
def sendToEurope(packet: Array[Byte]): Array[Byte]
}
val socket = Socket()
val packet = socket.readFromMemory()
// block for 250,000 ns
// only continue if there is no exception
val confirmation = socket.sendToEurope(packet)
// block for (more than) 150,000,000 ns
// only continue if there is no exception
Translation to human scale
1 nanosecond
->
1 second
(then hours/days/months/years)
Quizz - translate to human scale
1 nanosec -> 1 sec
execute typical instruction 1 nanosec fetch from L1 cache memory 0.5 nanosec branch misprediction 5 nanosec fetch from L2 cache memory 7 nanosec Mutex lock/unlock 25 nanosec fetch from main memory 100 nanosec send 2K bytes over 1Gbps network 20,000 nanosec read 1MB sequentially from memory 250,000 nanosec fetch from new disk location (seek) 8,000,000 nanosec read 1MB sequentially from disk 20,000,000 nanosec send packet US to Europe and back 150 milliseconds = 150,000,000 nanosecTranslation to human scale
1) Execute typical instruction
1 nanosec
->
1 second
Translation to human scale
2) Fetch from L2 cache memory
7 nanosec
->
a) 1 second
b) 17 second
c) 7 second
d) 0.7 second
Translation to human scale
3) Send 2K bytes over 1Gbps network
20,000 nanosec
->
a) 5.5 hours
b) 18 minutes
c) 3 days
d) 1 month
Translation to human scale
4) Read 1MB sequentially from memory
250,000 nanosec
->
a) 1.5 year
b) 19 hours
c) 3 days
d) 7 weeks
Translation to human scale
5) Fetch from new disk location (seek)
8,000,000 nanosec
->
a) 6 days
b) 5 months
c) 13 weeks
d) 3 years
Translation to human scale
6) Read 1MB sequentially from disk
20,000,000 nanosec
->
a) 27 days
b) 6.5 months
c) 9 years
d) 1.5 year
Translation to human scale
7) Send packet US to Europe and back
150 milliseconds = 150,000,000 nanosec
->
a) 5 years
b) 11 months
c) 17 years
d) 3 weeks
And the winner is...
Results
execute typical instruction 1 nanosec 1 sec fetch from L1 cache memory 0.5 nanosec 0.5 sec branch misprediction 5 nanosec 5 sec fetch from L2 cache memory 7 nanosec c) 7 sec Mutex lock/unlock 25 nanosec 0.5 min fetch from main memory 100 nanosec 1.5 min send 2K bytes over 1Gbps network 20,000 nanosec a) 5.5 hours read 1MB sequentially from memory 250,000 nanosec c) 3 days fetch from new disk location (seek) 8,000,000 nanosec c) 13 weeks read 1MB sequentially from disk 20,000,000 nanosec b) 6.5 months send packet US to Europe and back 150 milliseconds a) 5 yearsRead and send data
trait Socket {
def readFromMemory(): Array[Byte]
def sendToEurope(packet: Array[Byte]): Array[Byte]
}
val socket = Socket()
val packet = socket.readFromMemory()
// block for 3 days
// only continue if there is no exception
val confirmation = socket.sendToEurope(packet)
// block for 5 years
// only continue if there is no exception
Thank you
& have a good time
karol.kleibl@asseco-ce.com