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Date: Sun, 06 Nov 2005 14:30:40 -0600
From: Stephen Montgomery-Smith <stephen@math.missouri.edu>
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Subject: kernel: calcru: runtime went backwards
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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.)

Stephen