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@understeer
understeer / latency.txt
Created January 12, 2017 14:04 — forked from eshelman/latency.txt
HPC-oriented Latency Numbers Every Programmer Should Know
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
understeer / run-with-sequence-IPs.sh
Created May 17, 2016 03:49
プライベートIPアドレスを連番でインスタンスを起動する
#!/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
understeer / mpitest.c
Created March 10, 2014 10:32
OpenMPI test sample
/*
* Usage:
* mpicc mpitest.c -o mpitest
* mpirun -np 2 -H `hostname` ./mpitest
*/
#include <stdio.h>
#include <mpi.h>
int main(int argc, char *argv[])