Speaking of Linux, yes. You can echo mysterious numbers into /proc/sys/vm/drop_caches to flush various caches. http://jim.studt.net/depository/index.php/flushin

Speaking of Linux, yes. You can echo mysterious numbers into /proc/sys/vm/drop_caches to flush various caches. http://jim.studt.net/depository/index.php/flushing-caches-for-benchmarking-in-linux http://jim.studt.net/depository/index.php/flushing-caches-fo... for a one liner, http://linux-mm.org/Drop_Caches http://linux-mm.org/Drop_Caches for the info from the horse's mouth. As an example, consider running md5sum on a directory of 1436 jpeg files of about 50k each on an Atom 330 ( 2 dies, 2 hyperthreads/die). The 8way numbers use xargs with -n8 and -P8. The flushed cache entries indicate that all three caches have been flushed immediately before the command ... elapsed user system Cold cache: 11.98 0.56 1.75 ======================== second run: 2.71 1.38 1.76 ===== third run: 3.17 1.40 1.75 ====== flushed cache: 12.11 0.58 1.80 ======================== flushed cache, 8way: 12.64 1.00 2.27 ========================= second run, 8way: 1.22 1.15 2.52 == third run, 8way: 1.17 1.26 2.26 == I do not explain the oddity that user time seems abnormally low with flushed cache, or perhaps abnormally high with cache data present, particularly with the single threaded version.