clock time in milliseconds into a c program

[Alin-Adrian Anton]

Marco Trentini wrote:
> Hi, I need to clock the function execution time into a C
> program. I know /usr/include/time.h library but I need to
> clock the time in milliseconds.
> 
> Any suggestions, links?
> 

---snip---
#include <sys/time.h>

struct timeval tv1,tv2;
struct timezone tz1,tz2;

gettimeofday(&tv1,&tz1);

for (i=0;i<5000000;i++) {
         tmp=tree_insert(myroot,i,i+10); // cycles
         if (tmp) myroot=tmp; // cycles
}
gettimeofday(&tv2,&tz2);

fprintf(stderr,"Insertion of 5 billions lasted %d microseconds\n",
   ((tv2.tv_sec - tv1.tv_sec) * 1000000 + (tv2.tv_usec - tv1.tv_usec)));
---snip---

So you can measure the cycles multiple times then compute the average time.

For this snippet (which deals with a B+tree) i got results of the form 
0.3445866564 microseconds, which means 344.5867 miliseconds.. etc..

I don't think there is a streight way to speed-up the default unix time 
resolution, which is, as far as i know, in microseconds.

Regards,
-- 
Alin-Adrian Anton
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