process timing

[Slidey]

hola

im trying to time how long a program is running so as to get some sorta figures on bandwidth (data units per time period)

im using the following code: (condensed)

clock_t start, end;
struct tms t_start, t_end;

        start = times(&t_start);

then i call the function

i have a finishup function that is called when the program either gets an error or gets a SIGINT

void finishup(int exitval) {
        long tps = sysconf(_SC_CLK_TCK);
        end = times(&t_end);
        printf("elapsed: %6.2f secs\n", (float)(end - start)/tps);
        printf("caught ctrl-c, received %i packets, cleaning up\n", pktno);
        fclose(fout);
        fclose(procinfo);
        exit(exitval);
}

HOWEVER...!

the time it prints out is generally a lot less than the actual time it runs..

now i suspect its because im working on cpu time or thereabouts and not real time or IO time..

can anyone suggest a better way to do this (in C) as my books are at my birds

Slidey

[Structural Integrity]

In Windows there are two timers one can use:
The system clock
The CPU clock

One of these two is pretty inaccurate and is sometimes not refreshed at regular intervals...

The accurate one is:
float timeGetTime(void);

And requires these files to be included/linked:
#include <mmsystem.h> //used for timing (LINKED WITH winmm.lib)
#pragma comment(lib, "winmm.lib")

I guess you're working under Linux (since I've never seen times() before) but I wouldn't be surprised if there were two clocks under Linux too.

[Slidey]

i dont use windows

i dont own a windows machine

anyone else ?

[MT]

use gettimeofday()?

[mikay]

time command?