Blog :: 2011/09/...

Cluster 2011 Presentation
Posted 2011/09/29
This morning I presented the iso-energy-efficiency paper in the "Technical Papers: System Performance" session of Cluster 2011. The presentation went well and I had lots of people come to me after the session and during lunch to ask questions and make suggestions about measuring power in GPUs. I have uploaded [...]
Cluster 2011 Austin, TX
Posted 2011/09/26
Today I flew out to Austin to attend IEEE Cluster 2011. I am presenting the iso-energy-efficiency paper I wrote with Leon in May. Big change from Blacksburg weather, it is 100 degrees here! [...]
MPI where am I?
Posted 2011/09/22
Here is a simple MPI program which will print out the hostname of the node it is running on. By printing the hostname you can see where the process is being executed. whereami.c #include <stdio.h> #include <string.h> #include <stddef.h> #include <stdlib.h> #include "mpi.h" main(int argc, char **argv ) { int rank, size; [...]
Pthreads race condition demo
Posted 2011/09/14
Pthreads race condition The commented out lines will prevent the race condition. #include <pthread.h> #include <stdio.h> #include <stdlib.h> #define NTHREADS 100 #define LOOPS 10000 int sum = 0; pthread_mutex_t sum_mutex; void *do_work() { int i; //pthread_mutex_lock(&sum_mutex); for (i=0; i<LOOPS; i++) [...]