[rtl] Linux equivalents to pthread_make_periodic_np and pthread_suspend_np
Hello all: I'm trying to make DSLib v2 generate adecuatedsystem calls depending on it beingLinux, RTLinux, or RTAI. I'm looking in the Linux threads functions and I don't see any equivalent to pthread_make_periodic_np and pthread_suspend_np. Is there any?. If not, how can I performsuch operations?. Thank you. Ivan Martinez
Re: [rtl] Linux equivalents to pthread_make_periodic_np and pthread_suspend_np
On Fri, Apr 13, 2001 at 09:22:14PM +0200, Ivan Martinez wrote:
Hello all:
I'm trying to make DSLib v2 generate adecuated system calls depending on it being
Linux, RTLinux, or RTAI. I'm looking in the Linux threads functions and I don't see
any equivalent to pthread_make_periodic_np and pthread_suspend_np. Is there any?. If
not, how can I perform such operations?.
Thank you.
Ivan Martinez
It can be duplicated using something similar to the attached
file.
dave...
/* Example of a periodic task using straight POSIX calls. */
/* Copyright 2001 David Schleef [EMAIL PROTECTED] */
/* Use, distribution, and modification are allowed under the LGPL. */
#include stdio.h
#include stdlib.h
#include sys/time.h
#include sys/types.h
#include unistd.h
#define PERIOD 10 /* 100 ms */
void tv_add_usec(struct timeval *tv,unsigned int usec);
int tv_compare(struct timeval *a,struct timeval *b);
void tv_sub(struct timeval *a,struct timeval *b);
int main(int argc,char *argv[])
{
struct timeval now;
struct timeval next_tick;
gettimeofday(next_tick,NULL);
tv_add_usec(next_tick,PERIOD);
while(1){
printf("tick\n");
gettimeofday(now,NULL);
if(tv_compare(next_tick,now)0){
struct timeval timeout;
timeout = next_tick;
tv_sub(timeout,now);
select(0,NULL,NULL,NULL,timeout);
}
tv_add_usec(next_tick,PERIOD);
}
}
void tv_add_usec(struct timeval *tv,unsigned int usec)
{
tv-tv_usec += usec;
while(tv-tv_usec=100){
tv-tv_usec -= 100;
tv-tv_sec ++;
}
}
int tv_compare(struct timeval *a,struct timeval *b)
{
if(a-tv_sec==b-tv_sec)return b-tv_usec-a-tv_usec;
return b-tv_sec-a-tv_sec;
}
void tv_sub(struct timeval *a,struct timeval *b)
{
a-tv_sec -= b-tv_sec;
if(a-tv_usec b-tv_usec){
a-tv_usec += 100;
a-tv_sec --;
}
a-tv_usec -= b-tv_usec;
}
Re: [rtl] Linux equivalents to pthread_make_periodic_np and pthread_suspend_np
David Schleef schrieb:
It can be duplicated using something similar to the attached
file.
select() is not bad, but you can't guarantee a stable
period (means a delay is propagated to the following
periods).
For this reason, i prefer pthread_cond_timedwait()
(see file attached).
Suspending can be done by using pthread_cond_wait().
Bernhard
// gcc -Wall -O2 -I/usr/src/rtai/include -D__KERNEL__ -DMODULE -c rt_thread.c
#include linux/module.h
#include linux/kernel.h
#include linux/version.h
#include asm/io.h
#include rtai.h
#include rtai_sched.h
#include rtai_pthread.h
#define PORT 0x378
pthread_t thread_data;
pthread_mutex_t wait_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t wait_cond = PTHREAD_COND_INITIALIZER;
volatile int kill=0;
int position=0;
MODULE_PARM(position,"i");
void add_ns(struct timespec *time,long ns) {
time-tv_nsec+=ns;
time-tv_sec += time-tv_nsec/(10LL);
time-tv_nsec = time-tv_nsec%(10LL);
};
void thread_code(int arg) {
struct timespec time;
clock_gettime(CLOCK_REALTIME,time);
while(!kill) {
outb(0xff,PORT);
add_ns(time,100+position);
pthread_mutex_lock(wait_mutex);
pthread_cond_timedwait(wait_cond,wait_mutex,time);
pthread_mutex_unlock(wait_mutex);
outb(0x00,PORT);
add_ns(time,1900-position);
pthread_mutex_lock(wait_mutex);
pthread_cond_timedwait(wait_cond,wait_mutex,time);
pthread_mutex_unlock(wait_mutex);
};
kill=2;
pthread_exit(0);
};
int init_module(void) {
printk("rt_task: started, position=%i\n",position);
rt_set_oneshot_mode();
start_rt_timer(0);
pthread_create(thread_data,0,(void*)thread_code,0);
return 0;
};
void cleanup_module(void) {
kill=1;
while(kill!=2);
pthread_cond_destroy(wait_cond);
pthread_mutex_destroy(wait_mutex);
stop_rt_timer();
printk("rt_task: stopped, position=%i\n",position);
};
Re: [rtl] Linux equivalents to pthread_make_periodic_np and pthread_suspend_np
I've come to like pthread_cond_wait, although I admit that I found it
disgusting until recently -- when I wrote some applications where it
was quite pleasant.
On Sat, Apr 14, 2001 at 02:43:03AM +0200, Bernhard Kuhn wrote:
David Schleef schrieb:
It can be duplicated using something similar to the attached
file.
select() is not bad, but you can't guarantee a stable
period (means a delay is propagated to the following
periods).
For this reason, i prefer pthread_cond_timedwait()
(see file attached).
Suspending can be done by using pthread_cond_wait().
Bernhard
// gcc -Wall -O2 -I/usr/src/rtai/include -D__KERNEL__ -DMODULE -c rt_thread.c
#include linux/module.h
#include linux/kernel.h
#include linux/version.h
#include asm/io.h
#include rtai.h
#include rtai_sched.h
#include rtai_pthread.h
#define PORT 0x378
pthread_t thread_data;
pthread_mutex_t wait_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t wait_cond = PTHREAD_COND_INITIALIZER;
volatile int kill=0;
int position=0;
MODULE_PARM(position,"i");
void add_ns(struct timespec *time,long ns) {
time-tv_nsec+=ns;
time-tv_sec += time-tv_nsec/(10LL);
time-tv_nsec = time-tv_nsec%(10LL);
};
void thread_code(int arg) {
struct timespec time;
clock_gettime(CLOCK_REALTIME,time);
while(!kill) {
outb(0xff,PORT);
add_ns(time,100+position);
pthread_mutex_lock(wait_mutex);
pthread_cond_timedwait(wait_cond,wait_mutex,time);
pthread_mutex_unlock(wait_mutex);
outb(0x00,PORT);
add_ns(time,1900-position);
pthread_mutex_lock(wait_mutex);
pthread_cond_timedwait(wait_cond,wait_mutex,time);
pthread_mutex_unlock(wait_mutex);
};
kill=2;
pthread_exit(0);
};
int init_module(void) {
printk("rt_task: started, position=%i\n",position);
rt_set_oneshot_mode();
start_rt_timer(0);
pthread_create(thread_data,0,(void*)thread_code,0);
return 0;
};
void cleanup_module(void) {
kill=1;
while(kill!=2);
pthread_cond_destroy(wait_cond);
pthread_mutex_destroy(wait_mutex);
stop_rt_timer();
printk("rt_task: stopped, position=%i\n",position);
};
--
-
Victor Yodaiken
Finite State Machine Labs: The RTLinux Company.
www.fsmlabs.com www.rtlinux.com
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