Mark D. Hill, Michael R. Marty, "Amdahl's Law in the Multicore Era," Computer, vol. 41, no. 7, pp. 33-38, July 2008. IEEE Xplore link |
Base core equivalents : 1 BCE
Chip area/power limitations == n BCEs can be active on a chip
If you combine r cores, lets say we get a performance (single thread) of pref(r) < r.
Amdhal's law : Speedup (f, S) = 1 / [(1-f) + f/s]
Symmetric multicore chips S (f, n, r) = 1 / ( ( (1-f)/perf(r) ) + ( ( f*r)/perf(r)*n ) )
typically perf(r) = sqrt(r)
Asymmetric multicore S = 1 / ( (1-f) / perf(r) + f/ (perf(r) + n -r) )
dynamic = 1 / ( (1-f)/perf(r) + f/n ) )