#!/usr/bin/python # # Parameters of the memory system # # log2 of the memory capacity, in bytes param_capacity = 27 # log2 of the number of DRAM banks param_banks = 2 # log2 of the size of a DRAM row, in 32-bit words param_rowsize = 10 # burst length param_burstlength = 4 # dead time, per transaction param_deadtime = 2 # page miss penalty param_misspenalty = 6 # import sys def extract_bits(n, start, count): mask = 2**count - 1 return (n & (mask << start)) >> start def split_adr(adr): return extract_bits(adr, param_rowsize+param_banks, param_capacity-2-param_rowsize-param_banks+1), extract_bits(adr, param_rowsize, param_banks), extract_bits(adr, 0, param_rowsize) def count_page_hits(adrs): openrows = [0]*(2**param_banks) page_hits = 0 for adr in adrs: row, bank, col = split_adr(adr) if openrows[bank] == row: page_hits += 1 openrows[bank] = row return page_hits def reorder(adrs, window_size): window = [] openrows = [0]*(2**param_banks) def fetch_transaction(): for candidate in window: row, bank, col = split_adr(candidate) if openrows[bank] == row: window.remove(candidate) return candidate candidate = window[0] row, bank, col = split_adr(candidate) openrows[bank] = row window.remove(candidate) return candidate out = [] for adr in adrs: if len(window) == window_size: out.append(fetch_transaction()) window.append(adr) for i in range(0, window_size): out.append(fetch_transaction()) return out def print_page_hits(p, adrs): hit_rate = float(count_page_hits(adrs))/float(transaction_count) utilization = hit_rate*float(param_burstlength)/float(param_burstlength+param_deadtime) + (1.0-hit_rate)*float(param_burstlength)/float(param_deadtime+param_misspenalty+param_burstlength) print "%d, %d, %d" % (p, 100*hit_rate, 100*utilization) print "======= DRAM model parameters =======" print "Memory capacity: %dMB" % ((2**param_capacity)/(1024*1024)) print "DRAM banks: %d" % (2**param_banks) print "Row size: %d words (32-bit)" % (2**param_rowsize) print "Burst length: %d" % param_burstlength print "Dead time: %d" % param_deadtime print "Miss penalty: %d" % param_misspenalty print "======= Reading input... =======" transaction_count = 0 write_count = 0 unordered_adrs = [] for line in sys.stdin: adr = int(line, 16) >> 2 # express address in 32-bit words unordered_adrs.append(adr) if extract_bits(adr, param_capacity-2, 1) == 1: write_count = write_count + 1 transaction_count += 1 print "...done." print "Transaction count: %d" % transaction_count print "Writes: %d%%" % (100*write_count/transaction_count) print "Reads: %d%%" % (100*(transaction_count-write_count)/transaction_count) if write_count != 0: print "Reads/Writes: %.2f" % (float(transaction_count-write_count)/float(write_count)) print "======= Full reordering =======" print "(window size, page hit rate, utilization)" print_page_hits(1, unordered_adrs) for window_size in [2, 3, 4, 5, 6, 7, 8, 9, 10, 25, 50, 100]: reordered = reorder(unordered_adrs, window_size) print_page_hits(window_size, reordered)