Synergy User Manual and Tutorial. - THE CORE MEMORY
Synergy User Manual and Tutorial. - THE CORE MEMORY
Synergy User Manual and Tutorial. - THE CORE MEMORY
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<strong>Synergy</strong> <strong>User</strong> <strong>Manual</strong> <strong>and</strong> <strong>Tutorial</strong><br />
Throughput, also called capacity, is the rate that results arrive or the amount of work<br />
done in a given time. It is measured in the quantity of units per time. Megabits per<br />
second of data transmitted across a network, transactions completed per minute in a<br />
transaction server, <strong>and</strong> gigabytes of data per second transferred across a system buss are<br />
all throughput metrics. The theoretical maximum throughput is called b<strong>and</strong>width. The<br />
b<strong>and</strong>width of a 400Mhz, 64-bit data bus is 25.6Gb/s (400Mhz × 64-bit) but the actual<br />
throughput is less because of padding between data blocks <strong>and</strong> control protocols.<br />
The ratio of usable throughput compared to the b<strong>and</strong>width is called efficiency. The<br />
efficiency of a 400Mhz, 64-bit data bus, with a throughput of 20.48Gb/s, is 80%<br />
(20.48Gb/s ÷ 25.6Gb/s). Goodput is the arrival rate of good data packets across a<br />
computer network. If, on average, 920 packets arrive uncorrupted at the destination, the<br />
goodput is said to be 92%.<br />
Availability is the percentage of time that a system is available to provide service. If a<br />
server is down for 15 minutes each day for maintenance, it has 98.96% availability<br />
(1425min ÷ 1440min).<br />
The reliability metric reports the mean time between failures (MTBF), which indicates<br />
the average period that the system is usable. The mean time to repair (MTTR) is the<br />
average time to recover from failures.<br />
Utilization is the percentage of time that a component in the system is active. Utilization<br />
is typically measured as a percentage. The capacity or maximum throughput of a system<br />
is reached when the utilization of the busiest component is 100%. Many systems have a<br />
utilization threshold because as utilization approaches 100%, system latency quickly<br />
increases.<br />
Performance metrics for parallel systems include the following:<br />
• Runtime<br />
• Speedup<br />
• Efficiency<br />
• Cost<br />
• Scalability<br />
The run time of a parallel system is elapsed time from the instance of execution of the<br />
master or controller program until the last program in the parallel system terminates. T s<br />
usually denotes the serial or single processor run time of a task is <strong>and</strong> T p usually denotes<br />
the parallel run time.<br />
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