CODEWITHSUNDEEP
c++clinuxoperating-system
CDT
CDT

Reputation: 10621

Linux commands to detect the computer resource usage of a program

Suppose there are two programs a.out and b.out doing the same thing: sorting elements. a.out implements a QuickSort sorting algorithm, which takes O(nlogn) time and O(logn) memory, b.out implements a BubbleSort sorting algorithm, which takes O(n^2) time and O(1) memory. I want to gain some intuitive feelings of the time and memory comparison between these two algorithms, so is there any Linux command to measure the time and memory usage of a program after it is run ?

Upvotes: 2

Views: 1450

Answers (4)

cdarke
cdarke

Reputation: 44354

Programatically, I would use getrusage(), which allows you to measure single functions, and in a lot more detail than just time or top. For example:

#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>

int main (int argc, char *argv[])
{
    struct rusage start;
    struct rusage end;

    getrusage (RUSAGE_SELF, &start);    // get time at start

    some_function ();                   // Function to measure

    getrusage (RUSAGE_SELF, &end);      // get time at end

    printf ("System: %d usecs, User: %d usecs\n",
            end.ru_stime.tv_usec - start.ru_stime.tv_usec,
            end.ru_utime.tv_usec - start.ru_utime.tv_usec);
...

The rusage struct contains the following:

struct rusage {
    struct timeval ru_utime;    // user time used
    struct timeval ru_stime;    // system time used
    long   ru_maxrss;           // maximum resident set size
    long   ru_ixrss;            // integral shared memory size   
    long   ru_idrss;            // integral unshared data size
    long   ru_isrss;            // integral unshared stack size
    long   ru_minflt;           // page reclaims
    long   ru_majflt;           // page faults
    long   ru_nswap;            // swaps
    long   ru_inblock;          // block input operations
    long   ru_oublock;          // block output operations
    long   ru_msgsnd;           // messages sent
    long   ru_msgrcv;           // messages received
    long   ru_nsignals;         // signals received
    long   ru_nvcsw;            // voluntary context switches
    long   ru_nivcsw;           // involuntary context switches
};

Upvotes: 3

Maciek B
Maciek B

Reputation: 394

try time - time a simple command or give resource usage. The GNU version also reports memory usage:

/usr/bin/time --format="real\t%e\nuser\t%U\nsys\t%S\nmem:\t%M" -- ./a.out

Upvotes: 1

Yasir Malik
Yasir Malik

Reputation: 439

For getting time of the program, you can follow the following link. It shows how to use time command.

Get program execution time in the shell

For memory resources, please look at the following link for how to use top command in linux.

http://linux.about.com/od/commands/l/blcmdl1_top.htm

Upvotes: 1

suspectus
suspectus

Reputation: 17258

Use time which will give you real, user and system times of the programs. e.g.

  time ./a.out

The top command can be used for memory usage.

Upvotes: 1

Related Questions