gem5运行后统计数据stats.txt含义

参考：http://pl.it-usenet.org/thread/11778/3746/

gem5多级缓存运行命令：

build/ALPHA_FS/gem5.opt -d m5out/output/test --stats-file=statsbig.txt configs/example/fs.py --kernel=/dist/m5/system/binaries/vmlinux_2.6.27-gcc_4.3.4 -n 2 --script=benchmark/blackscholes_16c_test_ckpts.rcS --cpu-type=detailed --caches --l1i_size=32kB --l1d_size=32kB --l2cache --l2_size=4MB

sim_seconds is the amount of time simulated in seconds (程序真正的模拟时间)

sim_ticks is the amount of time simulated in “ticks” where some number of ticks are in a second (by default 1,000,000,000,000) host_seconds is the amount of time the simulation took in real time (how long you were staring at your watch for)（在主机上运行时间）