High resolution timer with C++ and Linux?

Question

Under Windows there are some handy functions like QueryPerformanceCounter from mmsystem.h to create a high resolution timer. Is there something similar for Linux?

http://stackoverflow.com/a/5524138/183120 (Cross-platform C++11 standard high resolution timer) — legends2k, May 15 '13 at 14:17

score 31 · Accepted Answer · edited May 23 '17 at 12:10

31

It's been asked before here -- but basically, there is a boost ptime function you can use, or a POSIX clock_gettime() function which can serve basically the same purpose.

edited May 23 '17 at 12:10

Community

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answered Feb 11 '09 at 20:29

Nik Reiman

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Didn't know that Boost provides timer functionality. Thank you :) – okoman Feb 11 '09 at 20:33
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Or use the [HighResTimer](http://www.dre.vanderbilt.edu/Doxygen/Stable/ace/classACE__High__Res__Timer.html) from the [ACE](http://www.cs.wustl.edu/~schmidt/ACE.html) library. – lothar Apr 12 '09 at 02:00
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@lothar: +1 for pointer to ACE library, thanks. The link you gave was stale, here's a new one: http://www.dre.vanderbilt.edu/Doxygen/Stable/libace-doc/a00227.html – BD at Rivenhill May 16 '11 at 16:02

score 30 · Answer 2 · edited May 23 '17 at 10:29

30

For Linux (and BSD) you want to use clock_gettime().

#include <sys/time.h>

int main()
{
   timespec ts;
   // clock_gettime(CLOCK_MONOTONIC, &ts); // Works on FreeBSD
   clock_gettime(CLOCK_REALTIME, &ts); // Works on Linux
}

See: This answer for more information

edited May 23 '17 at 10:29

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answered Feb 11 '09 at 20:30

grieve

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Of course, you need to be aware of the difference between `CLOCK_MONOTONIC` and `CLOCK_REALTIME` - the former has its zero-point set to something arbitrary at system boot, and as such is only useful for relative comparisons between two `CLOCK_MONOTONIC` measurements (but is unaffected by wallclock adjustments) – bdonlan Jan 21 '11 at 17:57

score 8 · Answer 3 · edited May 09 '18 at 05:44

8

Here's a link describing how to do high-resolution timing on Linux and Windows... and no, Don't use RTSC.

https://web.archive.org/web/20160330004242/http://tdistler.com/2010/06/27/high-performance-timing-on-linux-windows

edited May 09 '18 at 05:44

Somesh Kumar

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answered Jan 21 '11 at 16:54

tjd

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score 5 · Answer 4 · answered Aug 17 '16 at 18:48

With C++11, use std::chrono::high_resolution_clock.

Example:

#include <iostream>
#include <chrono>
typedef std::chrono::high_resolution_clock Clock;

int main()
{
    auto t1 = Clock::now();
    auto t2 = Clock::now();
    std::cout << "Delta t2-t1: " 
              << std::chrono::duration_cast<std::chrono::nanoseconds>(t2 - t1).count()
              << " nanoseconds" << std::endl;
}

Output:

Delta t2-t1: 131 nanoseconds

score 1 · Answer 5 · answered Feb 11 '09 at 20:28

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I have nothing but this link: http://www.mjmwired.net/kernel/Documentation/rtc.txt

I'm pretty sure RTC is what you are looking for though.

EDIT

Other answers seem more portable than mine.

answered Feb 11 '09 at 20:28

Oliver N.

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score 1 · Answer 6 · answered Jul 04 '11 at 21:44

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For my money, there is no easier-to-use cross-platform timer than Qt's QTime class.

answered Jul 04 '11 at 21:44

Alan Turing

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High resolution timer with C++ and Linux?

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