hi everyone,
as a follow up to the previous posting regarding
effects of measurment, I was testing gettimeofday().
The results that i got out of my test program were not
consistent and were varying. Wanted to get an opinion
abt it.
My test program:
----snip----
#include<stdio.h>
#include<stdlib.h>
#include<sys/time.h>
#include<sys/resource.h>
#include<errno.h>
extern int errno;
int main(int argc, char *argv[])
{
int loop_value = atoi(argv[1]);
int i=0;
long int diff=0;
struct timeval before,after;
gettimeofday(&before,NULL);
for (i = 0; i < loop_value; i++);
gettimeofday(&after,NULL);
diff = 1000000 * (after.tv_sec -
before.tv_sec);
diff += after.tv_usec - before.tv_usec;
fprintf(stderr,"the value of diff : %ld \n\n",
diff);
}
----snip----
The results that i got with the above test program are
:
----snip----
[root]# date
Wed Jul 17 23:42:50 EDT 2002
[root]#
[root]# ./try 10000000
the value of diff : 302839
[root]# ./try 10000000
the value of diff : 209972
[root]# ./try 10000000
the value of diff : 230121
[root]# ./try 10000000
the value of diff : 214455
[root]# ./try 10000000
the value of diff : 266560
[root]# ./try 10000000
the value of diff : 260128
[root]# ./try 10000000
the value of diff : 213221
[root]# ./try 10000000
the value of diff : 252402
[root]# ./try 10000000
the value of diff : 249561
[root]# ./try 10000000
the value of diff : 244444
[root]# ./try 10000000
the value of diff : 211876
[root]# ./try 10000000
the value of diff : 296651
[root]# ./try 10000000
the value of diff : 233641
[root]# ./try 10000000
the value of diff : 234075
[root]# date
Wed Jul 17 23:43:18 EDT 2002
[root]#
----snip-----
the values are varying a lot and did'nt have a clue
why it was the case. Did a little search on google but
could'nt find an answer.
TIA
Karthik
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