Startup Cost versus Throughput

[nnik]

Hwy guys, im trying to wrap my hear around this topic. Suppose we have a communication channel that connects a processor to main memory (DRAM) and to peripheral devices supports data transfers of two different sizes. 8 or 256 Bytes. Each transfer occupies the channel for a time period of 12ns for THE beginning plus 0.5 for every extra byte of data transferred. If this channel continuously transfers blocks of 8 Bytes stucback to back at the same time, then what is the thoughput of the channel, in MBytes/s? Will we account the starup cost or just measure the differencial cost and say we have 8bytes/0.5ns = 16 GBytes/s?

 

[D.A.(Tony)Stewart]

8 Bytes = 12 ns +0.5*8 = 16 ns or 0.5 GB/s
256 B = 12 ns + 0.5*256= 140 ns or 1.83 GB/s