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SubjectRe: [Lse-tech] Re: multi-queue scheduler update
On Thursday 18 January 2001 17:39, Andrea Arcangeli wrote:
> On Thu, Jan 18, 2001 at 04:52:25PM -0800, Mike Kravetz wrote:
> > was less than the number of processors. I'll give the tests a try
> > with a smaller number of threads. I'm also open to suggestions for
>
> OK!
>
> > what benchmarks/test methods I could use for scheduler testing. If
> > you remember what people have used in the past, please let me know.
>
> It was this one IIRC (it spawns threads calling sched_yield() in loop).
>
> /*
> Tester for the kernel's speed in scheduling.
> (C) 1999 / Willy Tarreau <willy@meta-x.org>
>
> Modified by Davide Libenzi <davidel@maticad.it>
>
>
> You can do whatever you want with this program, but I'm not
> responsible for any misuse. Be aware that it can heavily load
> a host. As it is multithreaded, it might take advantages of SMP.
>
> It basically creates a growing amount of threads and measures
> their cumulative work (i.e. loop iterations/second). The output
> is easily useable by gnuplot.
>
> To compile, you need libpthread :
>
> gcc -O2 -fomit-frame-pointer -o threads threads.c -lpthread
>
> Output on stdout is :
> <nb_threads> <average_work> <zero_work_threads> <std_deviation>
>
> */
>
> #include <stdio.h>
> #include <pthread.h>
> #include <signal.h>
> #include <unistd.h>
> #include <time.h>
>
>
>
> #define MAXTHREADS 450
> #define MEASURE_TIME 60
>
>
>
> pthread_t thr[MAXTHREADS];
> int nbthreads = MAXTHREADS;
> int measure_time = MEASURE_TIME;
> volatile actthreads = 0;
>
> long long int totalwork[MAXTHREADS];
> volatile int stop = 0,
> start = 0,
> count = 0;
>
> void oneatwork(int thr)
> {
> int i;
> while (!start) /* don't disturb pthread_create() */
> usleep(10000);
>
> actthreads++;
> while (!stop)
> {
> if (count)
> totalwork[thr]++;
>
> syscall(158); /* sys_sched_yield() */
> }
> actthreads--;
> pthread_exit(0);
> }
>
> main(int argc, char **argv)
> {
>
> int i,
> err,
> avgwork,
> thrzero;
> long long int value,
> avgvalue;
> double sqrdev;
> time_t ts,
> te;
>
> if (argc < 3)
> {
> printf("usage: %s threads time\n", argv[0]);
> exit(1);
> }
>
> nbthreads = atoi(argv[1]);
> measure_time = atoi(argv[2]);
>
>
> start = 0;
> count = 0;
> stop = 0;
> actthreads = 0;
> thrzero = 0;
> value = 0;
> sqrdev = 0.0;
>
> fprintf(stderr, "\nCreating %d threads ...", nbthreads);
> for (i = 0; i < nbthreads; i++)
> {
> if ((err = pthread_create(&thr[i], NULL, (void *) &oneatwork, (void
> *) i)) != 0) {
> fprintf(stderr, "thread %d pthread_create=%d -> ", i, err);
> perror("");
> exit(1);
> }
> pthread_detach(thr[i]);
> }
>
> for (i = 0; i < nbthreads; i++)
> totalwork[i] = 0;
>
> fprintf(stderr, " OK !\nWaiting for all threads to start ...");
>
> start = 1;
> while (actthreads != nbthreads)
> usleep(10000); /* waiting for a bit of stability */
>
> fprintf(stderr, "Go !\n");
>
> count = 1;
> time(&ts);
>
> sleep(measure_time);
>
> count = 0;
> stop = 1;
> time(&te);
>
>
> for (i = 0; i < nbthreads; i++)
> {
> value += totalwork[i];
> if (totalwork[i] == 0)
> ++thrzero;
> }
> avgvalue = value / nbthreads;
> value /= (int) difftime(te, ts);
> avgwork = (int) (value / nbthreads);
>
> for (i = 0; i < nbthreads; i++)
> {
> double difvv = (double) (totalwork[i] - avgvalue);
>
> sqrdev += difvv * difvv;
> }
>
> while (actthreads > 0)
> usleep(10000);
>
> printf("%d\t\t%lld\t\t%d\t\t%d\t\t%f\n", nbthreads, value, avgwork,
> thrzero, sqrdev / ((double) nbthreads * avgvalue * avgvalue));
>
> exit(0);
>
> }
>

Andrea found it before me :)


- Davide
-
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