If you use these functions your test will run in secondary mode. You
need to install the rtdm bcm2835_gpio driver for your test to stay in
the primary domain. Your tests at the moment are running as normal
linux applications even though you have built them with the Xenomai
libraries. You'll need enable the gpio module in the kernel build. You
should see the gpio pins under /dev/rtdm once the module is loaded. It
might be worth while posting your steps for building the application so
you can ensure you are indeed building the application to correctly
interface with Xenomai.
-Greg
On 2018-08-08 11:41 AM, Ho Tam wrote:
I used bcm2835 library for test, that library is implemented using
memory map (mmap). You may check its copied code here:
https://github.com/smart-facility/bcm2835/tree/master/src
The function I used bcm2835_gpio_write:
void bcm2835_gpio_write(uint8_t pin, uint8_t on)
{
if (on)
bcm2835_gpio_set(pin);
else
bcm2835_gpio_clr(pin);
}
I have also tested by direct using of bcm2835_gpio_set
and bcm2835_gpio_clr fucntions, but result was same as previous test:
for (i=0; i<500; ++i)
{
bcm2835_gpio_set(TEST_PIN);
bcm2835_gpio_clr(TEST_PIN);
}
Since functions in bcm2835 library usually call many other functions,
I have also implemented my own gpio library which directly read/write
value to GPSET and GPCLR:
for (i=0; i<3000; ++i)
{
*(rpi_gpio_mem_base+7) =(1<<TEST_PIN); //rpi_gpio_mem_base+7 ~ GPSET0
*(rpi_gpio_mem_base+10) =(1<<TEST_PIN); //rpi_gpio_mem_base+10 ~ GPCLR0
}
Here rpi_gpio_mem_base has been initialized with mmap before. In this
case, both process time and worst time reduce (for sure). But again,
worst time on rpi2,3 is larger than 350% process time, while for
rpi0,1 worst time ~ 120% process time.
Regards,
On Wed, Aug 8, 2018 at 8:12 PM Greg Gallagher <g...@embeddedgreg.com
<mailto:g...@embeddedgreg.com>> wrote:
How are you setting up the gpio read and write? Is it possible to
post a code snippet for the read and write?
Greg
Original Message
From: moph...@gmail.com <mailto:moph...@gmail.com>
Sent: August 8, 2018 6:45 AM
To: xenomai@xenomai.org <mailto:xenomai@xenomai.org>
Reply-to: moph...@gmail.com <mailto:moph...@gmail.com>
Subject: [Xenomai] Xenomai on Raspberry pi 2, 3 - Userspace task
is interrupted?
Hello all,
I make a simple code to measure process time on Raspberry pi
0,1,2,3 like:
* previous = rt_timer_read();*
* for (i=0; i<500; ++i)*
* {*
* bcm2835_gpio_write(TEST_PIN, HIGH);*
* bcm2835_gpio_write(TEST_PIN, LOW);*
* }*
* now = rt_timer_read();*
* process_time = (long) (now - previous);*
* if (process_time>worst_time)*
* worst_time=process_time;*
And I result after several hours running:
rpi process_time (us) worst_time (us)
0,1 ~100 115
2,3 ~90 373
It is clear that process time on rpi2,3 is shorter than that on
rpi0,1 due
to higher speed CPU. However, I don't understand why worst case on
rpi2,3
is much larger than that on rpi0,1. I have repeated this test on both
xenomai 2 and 3, kernel 4.1 and 4.9 (only xenomai 3 in this case)
and with
different task priority, the result is quite consistent.
Does anyone have explanation and solution?
Thanks and regards,
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