Alan,
Thank you for sharing the link.
I checked it and I understand CONFIG_USEC_PER_TICK(default 10000) is
important when using some functions like usleep().
It won't work well if I try usleep(10000) or shorter.
Thank you.
Yuta Ide
On 2021/04/30 2:49, Alan Carvalho de Assis wrote:
Hi Yuta,
Please read this documentation with more info about it:
https://cwiki.apache.org/confluence/display/NUTTX/Short+Time+Delays
BR,
Alan
On 4/29/21, yuta <yutr...@gmail.com> wrote:
Brennan,
Thank you for your advice.
I checked links you shared and
https://www.gnu.org/software/libc/manual/html_node/CPU-Time.html
I got elapsed time. Thank you.
However I'm wondering why the elapsed time I got was not exactly the same I
expected to get.
I tried below.
// ***** start
clock_t start, end;
double cpu_time_used;
start = clock();
usleep(1000000); // 1sec
end = clock();
cpu_time_used = ((double)(end - start)) / CLOCKS_PER_SEC;
printf("CPU time used: %f sec\n", cpu_time_used);
// ***** end
What I got is ...
"CPU time used: 1.010000 sec" (I expected to get 1.000000 sec)
Do you have any idea?
Yuta Ide
On 2021/04/30 0:30, Brennan Ashton wrote:
On Thu, Apr 29, 2021, 8:16 AM yuta <yutr...@gmail.com> wrote:
Hi all.
I'm new to NuttX.
I'm not sure if it's no problem me asking some personal question about
NuttX here. (please tell me if better place to ask.)
by the way, I have made my app in apps/examples/<my app>. It's working
well. Now, I would like to measure elapsed time during processing a
program by put codes like below.
NuttX supports the POSIX time interfaces so you are looking for something
like this.
https://www.gnu.org/software/libc/manual/html_node/Calculating-Elapsed-Time.html
There is also CPU time measurements, but NuttX does not treat this
exactly
correct as it is expected to give the amount of clock ticks the CPU has
spent on a process. Instead with NuttX you get ticks since boot.
https://www.gnu.org/software/libc/manual/html_node/Processor-And-CPU-Time.html
--Brennan
