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cputest.cpp
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cputest.cpp
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#include <iostream>
#include <vector>
#include <pthread.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
// Author: Troy Engel, I think? Maybe Keith Fralick.
// Not Andrew Howard, is the point here.
double CpuFrequency=3601.0; // CPU frequency in MHz
pthread_cond_t cv;
pthread_mutex_t m;
pthread_t thread2;
struct timeval before, after;
typedef unsigned long long ticks;
unsigned long long beforeTicks, afterTicks;
static __inline__ ticks getrdtsc()
{
unsigned a, d;
// asm("cpuid"); // We don't need to cause a pipeline stall for this test
asm volatile("rdtsc" : "=a" (a), "=d" (d));
return (((ticks)a) | (((ticks)d) << 32));
}
void *beginthread2(void *v)
{
for (;;)
{
// Wait for a signal from thread 1
pthread_mutex_lock(&m);
pthread_cond_wait(&cv, &m);
// Some dequeue op would normally be performed here after a spurious wake
// up test
// Get the ending ticks
afterTicks=getrdtsc();
pthread_mutex_unlock(&m);
// Display the time elapsed
std::cout << "Ticks elapsed: " << afterTicks-beforeTicks << " ("
<< (afterTicks-beforeTicks)/CpuFrequency << " us)\n";
}
return NULL;
}
int main(int argc, char *argv[])
{
int core1=0, core2=0;
if (argc < 3)
{
std::cout << "Usage: " << argv[0] << " producer_corenum consumer_corenum" << std::endl;
return 1;
}
// Get core numbers on which to perform the test
core1 = atoi(argv[1]);
core2 = atoi(argv[2]);
std::cout << "Core 1: " << core1 << std::endl;
std::cout << "Core 2: " << core2 << std::endl;
pthread_mutex_init(&m, NULL);
pthread_cond_init(&cv, NULL);
cpu_set_t cpuset;
CPU_ZERO(&cpuset);
CPU_SET(core1, &cpuset);
// Set affinity of the first (current) thread to core1
pthread_t self=pthread_self();
if (pthread_setaffinity_np(self, sizeof(cpu_set_t), &cpuset)!=0)
{
perror("pthread_setaffinity_np");
return 1;
}
CPU_ZERO(&cpuset);
CPU_SET(core2, &cpuset);
// Create second thread
pthread_create(&thread2, NULL, beginthread2, NULL);
// Set affinity of the second thread to core2
if (pthread_setaffinity_np(thread2, sizeof(cpu_set_t), &cpuset)!=0)
{
perror("pthread_setaffinity_np");
return 1;
}
// Run the test
for (;;)
{
// Sleep for one second
sleep(1);
// Get the starting ticks
beforeTicks=getrdtsc();
// Signal thread 2
pthread_mutex_lock(&m);
// Some enqueue op would normally be performed here
pthread_cond_signal(&cv);
pthread_mutex_unlock(&m);
}
}