How to win friends and influence benchmarks...
I note that I have a shell in my nc_test4 directory,
clear_cache.sh. I have to sudo to run it, but when I do, it has a
dramatic effect on the time that the time series read takes.
The following uses the new (not yet checked in) test program
tst_ar4_3d.c, which seeks to set up a simpler proxy data file for the
AR-4 tests. I want to show that a simpler file (but with the same-sized
data variable) has similar performance to the slightly more dressed up
pr_A1 file from AR-4 that I got from Gary. That's because my simpler
file is easier to create in a test program.
bash-3.2$ ./tst_ar4_3d -h cs[0] cs[1] cs[2] cache(MB) deflate shuffle read_hor(us) read_time_ser(us) 64 256 128 4.0 0 0 1420 2281847
bash-3.2$ ./tst_ar4_3d -h cs[0] cs[1] cs[2] cache(MB) deflate shuffle read_hor(us) read_time_ser(us) 64 256 128 4.0 0 0 81 3159
bash-3.2$ ./tst_ar4_3d -h cs[0] cs[1] cs[2] cache(MB) deflate shuffle read_hor(us) read_time_ser(us) 64 256 128 4.0 0 0 76 2983
bash-3.2$ sudo bash clear_cache.sh
bash-3.2$ ./tst_ar4_3d -h cs[0] cs[1] cs[2] cache(MB) deflate shuffle read_hor(us) read_time_ser(us) 64 256 128 4.0 0 0 1410 2504315
Wow, what a difference a cleared cache makes!
Here's the clear_cache.sh script:
#!/bin/bash -x # Clear the disk caches.
sync
echo 3 > /proc/sys/vm/drop_caches
