high resolution timer question

QNX Newsgroups (Archives) comp.os.qnx
1

I tried timer_create() function following the example in the QNX 6.2
Library Reference. The best
resolution I can get is 1 ms(0.001second). For clock_gettime(), it’s also
1ms resolution.
How can we set up a timer whose resolution is 0.1ms. Can we get the
more precise time measuring
,like 0.001ms resolution?

–
Tie Hu

2

How many nsec is the lowest clock period that we can set?
In the help it says that it is 10 microseconds (10000 ns). But the
lowest that i could set unti now it was 500 microseconds (500000 ns).
If i tried lower than 500us, it give me errno=22.

I have a PIII 800Mhz and QNX6.2.
Javier




Jens H Jorgensen wrote:

Look at ClockPeriod() to increase the real-time clock.

http://www.qnx.com/developer/docs/momentics_nc_docs/neutrino/lib_ref/c/clock
period.html

\

Jens
“tie” <> tie@cbis.ece.drexel.edu> > wrote in message
news:aeae2e$bke$> 1@inn.qnx.com> …

I tried timer_create() function following the example in the QNX 6.2
Library Reference. The best
resolution I can get is 1 ms(0.001second). For clock_gettime(), it’s also
1ms resolution.
How can we set up a timer whose resolution is 0.1ms. Can we get the
more precise time measuring
,like 0.001ms resolution?

–
Tie Hu

\

3

Look at ClockPeriod() to increase the real-time clock.

http://www.qnx.com/developer/docs/momentics_nc_docs/neutrino/lib_ref/c/clock
period.html

\

Jens
“tie” <tie@cbis.ece.drexel.edu> wrote in message
news:aeae2e$bke$1@inn.qnx.com…

I tried timer_create() function following the example in the QNX 6.2
Library Reference. The best
resolution I can get is 1 ms(0.001second). For clock_gettime(), it’s also
1ms resolution.
How can we set up a timer whose resolution is 0.1ms. Can we get the
more precise time measuring
,like 0.001ms resolution?

–
Tie Hu

4

I haven’t tried it myself - but I saw a post somewhere where they talked
setting it to100us successfully.

I know the documentation claims that you should be able to go down to 10us
with QNX 6.2. In QNX 6.1 there was a lower limit at 500us.

Jens

“Javier Barreiro” <jbarreiro@ingdesi.com> wrote in message
news:3D088942.9030901@ingdesi.com…

How many nsec is the lowest clock period that we can set?
In the help it says that it is 10 microseconds (10000 ns). But the
lowest that i could set unti now it was 500 microseconds (500000 ns).
If i tried lower than 500us, it give me errno=22.

I have a PIII 800Mhz and QNX6.2.
Javier




Jens H Jorgensen wrote:
Look at ClockPeriod() to increase the real-time clock.


http://www.qnx.com/developer/docs/momentics_nc_docs/neutrino/lib_ref/c/clock
period.html

\

Jens
“tie” <> tie@cbis.ece.drexel.edu> > wrote in message
news:aeae2e$bke$> 1@inn.qnx.com> …

I tried timer_create() function following the example in the QNX
6.2
Library Reference. The best
resolution I can get is 1 ms(0.001second). For clock_gettime(), it’s
also
1ms resolution.
How can we set up a timer whose resolution is 0.1ms. Can we get
the
more precise time measuring
,like 0.001ms resolution?

–
Tie Hu



\

5

Can this be difference between 6.2 NC vs SE/PE?

Jens
“Jens H Jorgensen” <jhj@remove-nospam-videk.com> wrote in message
news:aeaivb$f1o$1@inn.qnx.com…

I haven’t tried it myself - but I saw a post somewhere where they talked
setting it to100us successfully.

I know the documentation claims that you should be able to go down to 10us
with QNX 6.2. In QNX 6.1 there was a lower limit at 500us.

Jens

“Javier Barreiro” <> jbarreiro@ingdesi.com> > wrote in message
news:> 3D088942.9030901@ingdesi.com> …
How many nsec is the lowest clock period that we can set?
In the help it says that it is 10 microseconds (10000 ns). But the
lowest that i could set unti now it was 500 microseconds (500000 ns).
If i tried lower than 500us, it give me errno=22.

I have a PIII 800Mhz and QNX6.2.
Javier




Jens H Jorgensen wrote:
Look at ClockPeriod() to increase the real-time clock.



http://www.qnx.com/developer/docs/momentics_nc_docs/neutrino/lib_ref/c/clock
period.html

\

Jens
“tie” <> tie@cbis.ece.drexel.edu> > wrote in message
news:aeae2e$bke$> 1@inn.qnx.com> …

I tried timer_create() function following the example in the QNX
6.2
Library Reference. The best
resolution I can get is 1 ms(0.001second). For clock_gettime(), it’s
also
1ms resolution.
How can we set up a timer whose resolution is 0.1ms. Can we get
the
more precise time measuring
,like 0.001ms resolution?

–
Tie Hu





\

6

Javier Barreiro <jbarreiro@ingdesi.com> wrote:

How many nsec is the lowest clock period that we can set?
In the help it says that it is 10 microseconds (10000 ns). But the
lowest that i could set unti now it was 500 microseconds (500000 ns).
If i tried lower than 500us, it give me errno=22.

I tested this today. I got 10us on a 333Mhz AMD K6.

-David

QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.

7

Jens H Jorgensen <jhj@remove-nospam-videk.com> wrote:

Can this be difference between 6.2 NC vs SE/PE?

I would not expect so.

-David

QNX Training Services
http://www.qnx.com/support/training/
Please followup in this newsgroup if you have further questions.