Measuring CPU Time

QNX Newsgroups (Archives) comp.os.qnx
1

I have a task that runs every millisecond:

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
[task]; // Do something
}

What is the best way to measure how much CPU time [task] consumes each
cycle? I’m interested in QNX4 and Neutrino solutions, latter preferred.

Thanks
Markus

2

Check out ClockCycles() which will be from the processors internal
counter (pentuim and above)

Bill

On Tue, 31 Oct 2000 15:05:52 -0500, “Markus Loffler”
<loffler@ces.clemson.edu> wrote:

I have a task that runs every millisecond:

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
[task]; // Do something
}

What is the best way to measure how much CPU time [task] consumes each
cycle? I’m interested in QNX4 and Neutrino solutions, latter preferred.

Thanks
Markus

3

Thanks Bill,
I know about ClockCycles(). However, if I do

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
start = ClockCycles();
[task]; // Do something
stop = ClockCycles();
}

and a higher priority process interrupts my process (which can be the case),
wouldn’t the result be inaccurate?
Thanks
Markus


“William M. Derby Jr.” <derbyw@derbtronics.com> wrote in message
news:3a017185.1065964@inn.qnx.com…

Check out ClockCycles() which will be from the processors internal
counter (pentuim and above)

Bill

On Tue, 31 Oct 2000 15:05:52 -0500, “Markus Loffler”
loffler@ces.clemson.edu> > wrote:

I have a task that runs every millisecond:

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
[task]; // Do something
}

What is the best way to measure how much CPU time [task] consumes each
cycle? I’m interested in QNX4 and Neutrino solutions, latter preferred.

Thanks
Markus
\

4

Markus Loffler <loffler@ces.clemson.edu> wrote:

Thanks Bill,
I know about ClockCycles(). However, if I do

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
start = ClockCycles();
[task]; // Do something
stop = ClockCycles();
}

and a higher priority process interrupts my process (which can be the case),
wouldn’t the result be inaccurate?

on -p63 ./test_program

Nothing will stop you then! :slight_smile:

chris

–

cdm@qnx.com > “The faster I go, the behinder I get.”

Chris McKillop – Lewis Carroll –
Software Engineer, QSSL
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

5

Maybe you could make use of the getrusage() function.

Previously, Chris McKillop wrote in comp.os.qnx:

Markus Loffler <> loffler@ces.clemson.edu> > wrote:
Thanks Bill,
I know about ClockCycles(). However, if I do

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
start = ClockCycles();
[task]; // Do something
stop = ClockCycles();
}

and a higher priority process interrupts my process (which can be the case),
wouldn’t the result be inaccurate?

on -p63 ./test_program

Nothing will stop you then! > :slight_smile:

chris

–

cdm@qnx.com > “The faster I go, the behinder I get.”
Chris McKillop – Lewis Carroll –
Software Engineer, QSSL

6

Checkout the ClockId and ClockTime functions…

uint64_t start, stop, time_in_nanoseconds_spent_executing_in_this_process;

my_clock_id = ClockId( 0, this_tid );

ClockTime( my_clock_id, NULL, &start );
[…]
ClockTime( my_clock_id, NULL, &stop );

time_in_nanoseconds_spent_executing_in_this_process = stop - start;

Markus Loffler <loffler@ces.clemson.edu> wrote:

Thanks Bill,
I know about ClockCycles(). However, if I do

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
start = ClockCycles();
[task]; // Do something
stop = ClockCycles();
}

and a higher priority process interrupts my process (which can be the case),
wouldn’t the result be inaccurate?
Thanks
Markus



“William M. Derby Jr.” <> derbyw@derbtronics.com> > wrote in message
news:> 3a017185.1065964@inn.qnx.com> …

Check out ClockCycles() which will be from the processors internal
counter (pentuim and above)

Bill

On Tue, 31 Oct 2000 15:05:52 -0500, “Markus Loffler”
loffler@ces.clemson.edu> > wrote:

I have a task that runs every millisecond:

while (1)
{
Receive(…); // Waiting for a timer proxy/pulse
[task]; // Do something
}

What is the best way to measure how much CPU time [task] consumes each
cycle? I’m interested in QNX4 and Neutrino solutions, latter preferred.

Thanks
Markus

\

–
cburgess@qnx.com