hi everyone. If you have a function created in your code and you want to find out how long it takes for it to run you can use a struct called gettimeofday().
so lets say we have a function like this
int myfunction (int r)
{
/*some math calculations*/
return answer;
}
How do i set up gettimeofday to find out how long it takes for the function to run. thanks
Suggestion: use a profiler. Most UNIX systems compilers come with one.
You will get a display of how long your code spent in every function, plus the number of times it was called. The reason for the suggestion - it doesn't require instrumenting your code with timing calls.
The getTimeDiff function works on the two timeval structures to compute the seconds elapsed. The source is simple, and as follows:
Furthermore, it should be noted that clock() does *NOT* return values based upon real time, rather it returns CPU time. If you want to know how much REAL TIME something takes then clock() is not the solution. For example:
Upon running this code, you'll notice that the first two samples for clock are positioned squarely at 0. The sleep call, which will take around 2 seconds *real* time, has no effect on the second clock sample. Since sleep takes no CPU time, it is not calculated into the real time usage of the application by clock(). Similar behavior will be seen for other non-CPU (blocking) tasks the application incurs, such as waiting in a select call for socket I/O. The third clock sample, however, does incur CPU time as it is a CPU bound loop. Thus, the third sample will reflect the CPU time incurred by the loop. If, however, you had the crazy idea to insert (for example) a usleep in the loop, you would never calculate the additional real time incurred by the usleep.
So, beware that both methods, while equally useful, answer two different questions. clock() tells you CPU time used, the gettimeofday method tells you actual time elapsed.
I have noticed the difference in byte swap timing between two Ubuntu systems. The bswap_32 used to work just fine on the old system, but on the new one it lags behind home-grown swap.
My code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <byteswap.h>
#include... (4 Replies)
-> We have 2 servers server1 and server2 server.
->server1 is master application and server2 is slave application server. ->output of server1 hardware and slave timing:
# hwclock --show Thu 05 Jun 2014 05:34:08 PM SGT -0.465666 seconds # date Thu Jun 5 17:34:16 SGT 2014
# cd... (6 Replies)
I have 7 functions those need to be executed as command line inputs, I tried with below code it’s not executing function. If I run the ./script 2 then fun2 should execute , how to initiate that function I tried case and if else also, how to initiate function from command line
if
then... (8 Replies)
i have a very big script i have that i'd like to add a timeout to.
this script runs on a several remote host. i update this script with timeout clause and then copy it over to all the hosts on which it is currently on.
basically, i want the timeout to make the script abort/exit if it's... (1 Reply)
I was running some timings in my code to see which of several functions was the best and I've been getting some odd results. Here's the code I'm using:
static double time_loop(int (*foo)(int)) {
clock_t start, end;
int n = 0, i = 0;
start = clock();
for (; i <= MAXN; i++)
if... (6 Replies)
Hello there, I just needed to know how to get the timing right when using the gcc __builtin_prefetch() function, that is, how many instructions before the actual utilization of the data should I make the prefetch call.
I will be measuring the L1 cache hit rate with valgrind's cachegrind,... (3 Replies)
Hello everyone,
I have a script thats acting funky, what I would like to do is report to a file, how long its taking to get to certain area's, in seconds. For example.
-- Start timer
-- Run unix command 1
-- Run unix command 2
-- Stop timer
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-- etc etc
Is there a way... (3 Replies)
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hi guys..
i have a shell script that loops through a certain directory to see if a file has been created and then prints the file if it exists...
the only problem i have now is that sometimes the flat does not get created by the program thats supposed to create it, in this scenario, my loop... (1 Reply)