kernel: calcru: runtime went backwards

[Giovanni P. Tirloni]

Stephen Montgomery-Smith wrote:
> This is on a recent FreeBSD-6.0 stable SMP machine.
> 
> As root, run "top -s0".  Then, at the same time run this program:
> 
> #include <pthread.h>
> #define D (1<<10)
> void *thread(void *n) {
>   int i;
>   double array[D];
>   for (i=0;i<D;i++) array[i] = i;
> }
> int main() {
>   void *i;
>   pthread_t tid;
>   while (1) {
>     pthread_create(&tid,NULL,thread,i);
>     pthread_join(tid,&i);
>   }
> }
> 
> Let this program run for about a minute.  Then kill this program.
> 
> At this point, I sometimes get some calcru messages from the kernel.
> 
> (This is not a contrived situation - this happens much more frequently 
> than this sample program when I run programs with threaded fftw3 calls - 
> I suspect that it throws off the cpu times shown by top.)

Try this,

  http://www.freebsd.org/doc/en/books/faq/book.html#CALCRU-NEGATIVE

--
Giovanni P. Tirloni
http://tirloni.blogspot.com