b_loco
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Real time in C, as in the UNIX time command
Hi !
I have to measure the execution time of several functions in a C program I wrote.
What I have now is this:
struct tms StartTime;
struct tms EndTime;
float StartTimeSeconds;
float EndTimeSeconds;
times(&StartTime);
...
times(&EndTime);
StartTimeSeconds = (float)StartTime.tms_utime
EndTimeSeconds = (float)EndTime.tms_utime/(
float t_total;
t_total = EndTimeSeconds-StartTimeSe
I executed the program and the time of execution displayed was:
Execution time: 0.000066 seconds
I executed the UNIX time comand (as in "time program") and the result was:
Execution time: 0.000066 seconds
real 0m8.336s
user 0m0.660s
sys 0m0.240s
I could get to the user time by shifting the "." (sorry my english, hope you understand), but that's not what I want, I want the real time, even though I know that it takes in account the whole system and not just my program.
By changing the time field from tms_utime to tms_stime I can get the value of sys, but I can't get the real time
(by the way the "real" time was really about 8 secs).
How can this be achieved?
Thanks in advance
I have to measure the execution time of several functions in a C program I wrote.
What I have now is this:
struct tms StartTime;
struct tms EndTime;
float StartTimeSeconds;
float EndTimeSeconds;
times(&StartTime);
...
times(&EndTime);
StartTimeSeconds = (float)StartTime.tms_utime
EndTimeSeconds = (float)EndTime.tms_utime/(
float t_total;
t_total = EndTimeSeconds-StartTimeSe
I executed the program and the time of execution displayed was:
Execution time: 0.000066 seconds
I executed the UNIX time comand (as in "time program") and the result was:
Execution time: 0.000066 seconds
real 0m8.336s
user 0m0.660s
sys 0m0.240s
I could get to the user time by shifting the "." (sorry my english, hope you understand), but that's not what I want, I want the real time, even though I know that it takes in account the whole system and not just my program.
By changing the time field from tms_utime to tms_stime I can get the value of sys, but I can't get the real time
(by the way the "real" time was really about 8 secs).
How can this be achieved?
Thanks in advance
Sjef Bosman
Use long time(&long) twice, once at the start, one at the end of the program. Granularity: 1 second :( There might be more sophisticated calls, depending on the actual Unix version you have.
ASKER
I didn't quite understand your reply
you mean instead of :
times(&StarTime);
I should put:
long time(&long);
About the granularity, if i understood correctly, that wouldn't be a problem because the program is supposed to take more than 5 secs.
And I do not wish to make my program dependant to the OS so the more general the better. If required I would make it UNIX dependant, but I would like to avoid it.
you mean instead of :
times(&StarTime);
I should put:
long time(&long);
About the granularity, if i understood correctly, that wouldn't be a problem because the program is supposed to take more than 5 secs.
And I do not wish to make my program dependant to the OS so the more general the better. If required I would make it UNIX dependant, but I would like to avoid it.
ASKER CERTIFIED SOLUTION
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ASKER
That incredibly simple solution solved it
Thank you :)
Thank you :)