Download Analyzing Computer System Performance with Perl::PDQ by Neil J. Gunther PDF

throughput(bandwidth usage) increase it depends on the context. in reality, Latency & Throughput are two completely different metrics associated with "performance". Latency isn’t related to Throughput and vice-versa. Interestingly, this quote comes from a network engineer at Cisco Systems and, as you’ll see shortly, the operation of packet-network systems has biased his view of the relationship between throughput and latency metrics.

In between, however, we have some efficiency values that are in excess of 100%. If we plot these values separately, we see that except for the first data point, all the other data points in the dark area are illegal. Something is wrong. 0 and descend monotonically toward the x-axis. You can see why some efficiencies exceed 100% by looking at the second column (the relative capacity) in the Excel spreadsheet. , then you have a lot of explaining to do! On the other hand, if we ignore this problem and simply press on regardless, we run into trouble in the fourth column in Fig.

Consider transmitting a command to one of the two Voyager spacecraft, now roughly half a light-day from earth. Both spacecraft were launched in 1977 and are now more than 100 AU from earth. One AU (Astronomical Unit) is the distance from the earth to the sun: approximately 93 million miles. So it currently takes about 12 hours to send a command to either Voyager spacecraft and an equal amount of time for the spacecraft to return a response to the NASA deep space network (DSN). Therefore, the round trip time for an acknowledged transmission sequence takes a full light-day and, since Einstein told us that the speed of light c is a universal constant, there is nothing we can do to reduce that latency.

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