很多时候查不到本机cpu的cache信息。而了解这些信息，对于调优很有帮助

查看1级缓存cache大小

cat /sys/devices/system/cpu/cpu0/cache/index1/size

查看能访问这个1级缓存的cpu编号

cat /sys/devices/system/cpu/cpu0/cache/index1/shared_cpu_list

查看1级缓存cache line的大小

cat /sys/devices/system/cpu/cpu0/cache/index1/coherency_line_size

查看1级缓存cache set的数目

cat /sys/devices/system/cpu/cpu0/cache/index1/number_of_sets

查看2级缓存大小

cat /sys/devices/system/cpu/cpu0/cache/index2/size

查看其他级别的缓存可以更改index后的数字

cache_size = number_of_sets * cache_line_size * line_per_set

会导致cache miss率提高的vector size

criticalStride = number_of_sets * cache_line_size

参考：

http://*.com/questions/11413855/why-is-transposing-a-matrix-of-512x512-much-slower-than-transposing-a-matrix-of

http://www.7-cpu.com/cpu/SandyBridge.html

http://www.7-cpu.com/cpu/Westmere.html