understeer

Latency Comparison Numbers
--------------------------
L1 cache reference/hit                       1.5 ns                      4 cycles
Floating-point add/mult/FMA operation        1.5 ns                      4 cycles
L2 cache reference/hit                       5   ns                      12 ~ 17 cycles
Branch mispredict                            6   ns                      15 ~ 20 cycles
L3 cache hit (unshared cache line)          16   ns                      42 cycles
L3 cache hit (shared line in another core)  25   ns                      65 cycles
Mutex lock/unlock                           25   ns
L3 cache hit (modified in another core)     29   ns                      75 cycles

understeer

#!/bin/sh
INSTANCE_TYPE=c4.8xlarge

for IP in `seq 101 157`
do
 aws ec2 run-instances \
 --region ap-northeast-1 \
 --image-id ami-xxxxxx \
 --security-group-ids sg-xxxxx \
 --key-name test20140204 \

understeer

/*
 * Usage:
 * mpicc mpitest.c -o mpitest
 * mpirun -np 2 -H `hostname` ./mpitest
 */

#include <stdio.h>
#include <mpi.h>

int  main(int argc, char *argv[])