Re: [Valgrind-users] Scheduler problem

[Julian S. <js...@ac...>]

Sefer,

I tested the program you sent me (below) and it behaves
identically running on V from normal; no timing anomalies.
This is running on a 1133Mhz PIII-T (desktop) machine.

I suspect Jeremy may be right about the power management thing;
he's had a patch available for that for a while.  Can you 
clarify the situation re power management on your platform?
Thanks.

J

#include <pthread.h>
#include <stdio.h>
#include <unistd.h>


void *start(void *p)
{
        printf("Hi!\n");
        sleep(1);
        printf("Here\n");
        sleep(1);

        return 0;
}


int main()
{
        pthread_t tid;
        void *p;
        int i;

        for ( i = 0; i < 5; ++i ) {
                pthread_create(&tid, 0, start, 0);
        }
        pthread_join(tid, &p);

        return 0;
}

On Tuesday 08 April 2003 10:12 am, Jeremy Fitzhardinge wrote:
> Quoting Sefer Tov <se...@ho...>:
> > Hi!
> >
> > I've been testing a short threaded program, and I noticed that sleep(x),
> >
> > although utilizes no cpu, it schdules poorly (the program slows down
> > almost
> > to a halt).
>
> Is your machine a laptop, or a desktop with power management enabled? 
> Valgrind uses the TSC register as its timebase, and I've noticed on my
> laptop the TSC doesn't advance when the machine is idle.  You can easily
> tell if this is the case: if you run a CPU-bound program at the same time,
> then the TSC advances at near full speed and the sleeps are for the right
> time.
>
> 	J