Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

difftime() seems to have a resolution of 1 second - anything more accurate?

Posted on 2004-09-20
2
798 Views
Last Modified: 2012-05-05
Hi,

Difftime seems to have a resolution of 1 second, ie:

                              //
                              // Profiling: output time since last operation
                              //
                              {
                                    time(&profiling_now);
                                    time_t td;
                                    td=difftime(profiling_now, profiling_then);
                                    td=(float)td;
                                    my_fprintf_VL7(stderr,"[t2=%2.3fs]",td);
                                    time(&profiling_then);
                              }

... prints  things like [t2=1.000s] or [t2=3.000s].

Any calls in the Linux 2.6 kernel that can get a resolution down to 1/100 of a second? This excludes driver calls - this is an application.

Shane.
0
Comment
Question by:Risky101
2 Comments
 
LVL 23

Accepted Solution

by:
brettmjohnson earned 125 total points
ID: 12109178
time_t is number of seconds since 1970, so subtracting two values will give a
value with 1-second resolution.  You want to check out the gettimeofday() function,
which returns the following structure:

     struct timeval {
             long    tv_sec;         /* seconds since Jan. 1, 1970 */
             long    tv_usec;        /* and microseconds */
     };

It would be trivial to write a function that subtracts two timeval structures,
returning 1/100s of a second.

0
 
LVL 3

Expert Comment

by:scn
ID: 12111615
The macro timersub defined in sys/time.h performs substractions of timeval structure variables
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Have you ever been frustrated by having to click seven times in order to retrieve a small bit of information from the web, always the same seven clicks, scrolling down and down until you reach your target? When you know the benefits of the command l…
The purpose of this article is to fix the unknown display problem in Linux Mint operating system. After installing the OS if you see Display monitor is not recognized then we can install "MESA" utilities to fix this problem or we can install additio…
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question