Hi Everyone
I'm programming a little client-server application to test network performances
with xenomai 2.3.1 and rtnet 0.9.9.
The 2 programs are based on the rtnet frag-ip example.
The perdiodic scenario is :
- RSG program sends a datagram to the REMOTE program which was waiting.
- REMOTE sends a response to RSG.
- RSG simulates a CPU performing period using rt_timer_spin.
This cycle should take less than 2.5ms.
I observe strange time measurement :
For example when I want to run during 10 secs : 1000 cycles of 10 ms
The program calculates a time between 16 and 17 secs (using rt_timer_tsc)
But the effective elapsed time (i kept time with a chrono :-s ) is around 10secs
When a cycle is supposed to be 5ms it is calculated to be 8.4ms
When I want a rt_timer_spin of 0.750ms, result is a 1.27ms burning period.
So a constant difference between effective and calculated time around +60%.
Maybe there something wrong in my program but I don't know what.
Also, I have read some threads that mentionned time problem and
/proc/xenomai/latency value.
I didn't understand everything.
Any suggestion ?
Thanks in advance.
Niry
RSG program
/**
* \brief Prototype 01
* Runs a task that : - sends amount of data via UDP/IP to a remote box
* - waits for data message during a specific time
* - simulates a CPU calcul performing
* Time is expressed in nanoseconds
* \file rt_rsg.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/mman.h>
#include <arpa/inet.h>
#include <errno.h>
#include <native/task.h>
#include <native/timer.h>
#include <rtnet.h>
typedef unsigned long long uint64;
typedef unsigned long uint32;
/* --s--s--s */
/* s m u n */
#define ONE_SEC 1000000000ULL
#define ONE_MILLI 1000000ULL
#define ONE_MICRO 1000ULL
#define CYCLE_RSG 2500000ULL /* 2.5 ms */
#define ONE_KILO 1024
//#define CYCLE ONE_SEC
#define BUFF_SIZE ONE_KILO + 512
#define PORT 37001
/** remote parameters */
char *dest_ip_s = "192.168.0.10";
struct sockaddr_in dest_addr;
/** communication parameters */
unsigned int data_size = BUFF_SIZE;
unsigned int nb_data = 1;
unsigned int add_rtskbs = 75;
unsigned int cpt, nb_cycles;
/** time parameters */
uint64 start_time = 0;
uint64 **time_grid;
uint64 period = 5 * ONE_MILLI;
uint64 delay =10 * ONE_SEC;
uint64 recv_timeout = 20 * ONE_MILLI;
uint64 burn_time = 750 * ONE_MICRO;
RT_TASK rt_rsg_task;
FILE * fd;
int sock;
char buffer_out[BUFF_SIZE];
char buffer_in[BUFF_SIZE];
compute_time(int nb_values, char *file_name )
{
int i;
uint64 xr_time, tot_time, burn_time;
fd = fopen(file_name,"w+");
if (fd == NULL){
perror("Impossible d'ouvrir le fichier");
exit(2);
}
fprintf(fd,"# Duree %llu\n# Repeat %d\n# StartTime %llu\n# \n",
delay, nb_values, start_time);
fprintf(fd,"# Cycle AbsoluteTime XmitRecvTime TaskTime
CPUBurningTime\n");
/* Calcul des temps xmit - recv */
for (i = 0; i < nb_values; i++) {
xr_time = time_grid[i][1] - time_grid[i][0];
tot_time = time_grid[i][2] - time_grid[i][0];
burn_time = time_grid[i][2] - time_grid[i][1];
fprintf(fd,"%d %llu %llu %llu %llu\n",i,
time_grid[i][0], xr_time, tot_time, burn_time);
//fprintf(fd,"%d %llu %llu %llu\n",i, time_grid[i][0],
time_grid[i][1], time_grid[i][2]);
}
fclose(fd);
}
int burn_cpu(uint64 time)
{
rt_timer_spin(time);
}
int xmit_data()
{
int ret, i;
struct msghdr msg;
struct iovec iov[3];
unsigned short msgsize = data_size;
unsigned short nbmsg = nb_data;
for (i=0;i<nb_data;i++) {
iov[0].iov_base = &msgsize;
iov[0].iov_len = sizeof(msgsize);
iov[1].iov_base = buffer_out;
iov[1].iov_len = data_size;
iov[2].iov_base = &nbmsg;
iov[2].iov_len = sizeof(nbmsg);
memset(&msg, 0, sizeof(msg));
msg.msg_name = &dest_addr; // ptr addresse socket
msg.msg_namelen = sizeof(dest_addr); // longueur addresse socket
msg.msg_iov = iov; // tampon memoire vectoriel
msg.msg_iovlen = 3; // nb elements de msg_iov
// printf("Sending message of %d+2 bytes\n", size);
ret = rt_dev_sendmsg(sock, &msg, 0);
if (ret == -EBADF)
return ret;
else if (ret != (int)(sizeof(nbmsg) + sizeof(msgsize) +
data_size)) {
printf("*** Error *** rt_dev_sendmsg() = %d : %s\n",
ret, strerror(-ret));
return ret;
} /*else {
printf("emit data OK\n");
}*/
}
return 0;
}
int recv_data()
{
int ret;
struct msghdr msg;
struct iovec iov[3];
unsigned short msgsize = data_size;
unsigned short nbmsg = nb_data;
struct sockaddr_in addr;
iov[0].iov_base = &msgsize;
iov[0].iov_len = sizeof(msgsize);
iov[1].iov_base = buffer_in;
iov[1].iov_len = data_size;
iov[2].iov_base = &nbmsg;
iov[2].iov_len = sizeof(nbmsg);
memset(&msg, 0, sizeof(msg));
msg.msg_name = &addr;
msg.msg_namelen = sizeof(addr);
msg.msg_iov = iov;
msg.msg_iovlen = 2;
ret = rt_dev_recvmsg(sock, &msg, 0);
if (ret <= 0) {
printf("Error rt_dev_recvmsg() = %d : %s\n", ret,
strerror(-ret));
return ret;
} /*else {
unsigned long ip = ntohl(addr.sin_addr.s_addr);
printf("received data OK\n");
// printf("received packet from %lu.%lu.%lu.%lu, length: %zd+2, "
// "encoded length: %d,\n flags: %X, content
%s\n", ip >> 24,
// (ip >> 16) & 0xFF, (ip >> 8) & 0xFF, ip & 0xFF,
// ret-sizeof(msgsize), msgsize, msg.msg_flags,
// (memcmp(buffer_in, buffer_out, ret-sizeof(msgsize)) == 0) ?
// "ok" : "corrupted");
}*/
return 0;
}
void catch_signal(int sig)
{
}
void perform_rsg(void *arg)
{
int ret;
if((ret = rt_task_set_periodic (NULL, TM_NOW, period))) {
printf("ERROR : rt_task_set_periodic : %d\n", ret);
return;
}
start_time = rt_timer_ticks2ns(rt_timer_tsc());
while(1) {
if(cpt<nb_cycles) {
time_grid[cpt][0] = rt_timer_ticks2ns(rt_timer_tsc());
if(!xmit_data()) {
if(!recv_data()) {
time_grid[cpt][1] =
rt_timer_ticks2ns(rt_timer_tsc());
burn_cpu(burn_time);
}
}
time_grid[cpt][2] = rt_timer_ticks2ns(rt_timer_tsc());
cpt++;
}
if(cpt==nb_cycles) {
printf("No cycles remaining. Press ctl-c to quit.\n");
cpt++;
}
rt_task_wait_period(NULL);
}
}
int main(int argc, char *argv[])
{
int ret;
unsigned int i;
char *res_file_name = "res_tmp.txt";
struct sockaddr_in local_addr;
struct in_addr dest_ip;
uint64 chrono[2];
while (1) {
switch (getopt(argc, argv, "d:f:")) {
case 'd':
dest_ip_s = optarg;
break;
case 'f':
res_file_name = optarg;
break;
case -1:
goto end_of_opt;
default:
printf("usage: %s [-d <dest_ip>]\n", argv[0]);
return 0;
}
}
end_of_opt:
inet_aton(dest_ip_s, &dest_ip);
signal(SIGTERM, catch_signal);
signal(SIGINT, catch_signal);
signal(SIGHUP, catch_signal);
mlockall(MCL_CURRENT|MCL_FUTURE);
printf("*** Infos *** destination ip address %s=%08x\n", dest_ip_s,
dest_ip.s_addr);
printf("*** Debug *** size %d\n", data_size);
/* fill output buffer with test pattern */
for (i = 0; i < sizeof(buffer_out); i++)
buffer_out[i] = i & 0xFF;
printf("*** Debug *** CPU burning time : %llu\n",burn_time);
cpt = 0;
printf("*** Debug *** Total Duration : %llu\n",delay);
printf("*** Debug *** Cycle Duration : %llu\n",period);
nb_cycles = delay / period;
printf("*** Debug *** Number of cycles : %lu\n",nb_cycles);
time_grid = (uint64 **) malloc(sizeof(uint64 *) * nb_cycles);
for(i = 0; i < nb_cycles; i++)
time_grid[i] = (uint64 *) calloc(3, sizeof(uint64));
/* create rt-socket */
sock = rt_dev_socket(AF_INET,SOCK_DGRAM,0);
if (sock < 0) {
printf("*** Error *** rt_dev_socket() = %d!\n", sock);
return sock;
} else {
printf("*** Debug *** Creating socket OK\n");
}
/* extend the socket pool */
ret = rt_dev_ioctl(sock, RTNET_RTIOC_EXTPOOL, &add_rtskbs);
if (ret != (int)add_rtskbs) {
printf("*** Error *** rt_dev_ioctl(RT_IOC_SO_EXTPOOL) = %d\n",
ret);
rt_dev_close(sock);
return -1;
} else {
printf("*** Debug *** Extending socket pool OK\n");
}
/* reception acquitement bloquant + timeout */
ret = rt_dev_ioctl(sock, RTNET_RTIOC_TIMEOUT, &recv_timeout);
if (ret != 0) {
printf("*** Error *** rt_dev_ioctl(RT_IOC_TIME_OUT) = %d\n",
ret);
rt_dev_close(sock);
return -1;
} else {
printf("*** Debug *** Setting receive timeout OK\n");
}
/* bind the rt-socket to a port */
memset(&local_addr, 0, sizeof(struct sockaddr_in));
local_addr.sin_family = AF_INET;
local_addr.sin_port = htons(PORT);
local_addr.sin_addr.s_addr = INADDR_ANY;
ret = rt_dev_bind(sock, (struct sockaddr *)&local_addr,
sizeof(struct sockaddr_in));
if (ret < 0) {
printf("*** Error *** rt_dev_bind() = %d!\n", ret);
rt_dev_close(sock);
return ret;
} else {
printf("*** Debug *** Binding socket OK\n");
}
/* set destination address */
memset(&dest_addr, 0, sizeof(struct sockaddr_in));
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(PORT);
dest_addr.sin_addr = dest_ip;
ret = rt_task_create(&rt_rsg_task, "RSG", 0, 10, 0);
if (ret != 0) {
printf("*** Error *** rt_task_create(recv) = %d!\n", ret);
rt_dev_close(sock);
return ret;
}
rt_task_start(&rt_rsg_task, perform_rsg, NULL);
pause();
/* Note: The following loop and the strict ordering "close before task
* termination" is no longer required since Xenomai 2.4. */
while (rt_dev_close(sock) == -EAGAIN) {
printf("*** Debug *** Socket busy - waiting...\n");
sleep(1);
}
if(ret = rt_task_delete(&rt_rsg_task)) {
printf("*** Error *** rt_task_delete() = %d!\n", ret);
} else {
printf("*** Debug *** Deleting task OK\n");
}
compute_time(nb_cycles, res_file_name);
return 0;
}
REMOTE program
/**
* \brief Prototype 01
* Runs a task that : - waits for amount of data via UDP/IP from a remote box
* - sends data message
* Time is expressed in nanoseconds
* \file rt_remote.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/mman.h>
#include <arpa/inet.h>
#include <errno.h>
#include <native/task.h>
#include <native/timer.h>
#include <rtnet.h>
typedef unsigned long long uint64;
typedef unsigned long uint32;
/* --s--s--s */
/* s m u n */
#define ONE_SEC 1000000000ull
#define ONE_MILLI 1000000ull
#define ONE_MICRO 1000ull
#define ONE_KILO 1024
//#define CYCLE 2.5 * ONE_MILLI /* 2.5 ms */
#define CYCLE ONE_SEC
#define BUFF_SIZE ONE_KILO + 512
#define PORT 37001
/** remote parameters */
char *dest_ip_s = "192.168.0.1";
struct sockaddr_in dest_addr;
/** communication parameters */
unsigned int data_size = BUFF_SIZE;
unsigned int nb_data = 1;
unsigned int add_rtskbs = 75;
/** time parameters */
uint64 start_time;
uint64 *time_grid;
uint64 recv_timeout = CYCLE;
RT_TASK rt_rsg_task;
int sock;
char buffer_out[BUFF_SIZE];
char buffer_in[BUFF_SIZE];
int xmit_data()
{
int ret, i;
struct msghdr msg;
struct iovec iov[3];
unsigned short msgsize = data_size;
unsigned short nbmsg = nb_data;
iov[0].iov_base = &msgsize;
iov[0].iov_len = sizeof(msgsize);
iov[1].iov_base = buffer_out;
iov[1].iov_len = data_size;
iov[2].iov_base = &nbmsg;
iov[2].iov_len = sizeof(nbmsg);
memset(&msg, 0, sizeof(msg));
msg.msg_name = &dest_addr; // ptr addresse socket
msg.msg_namelen = sizeof(dest_addr); // longueur addresse socket
msg.msg_iov = iov; // tampon memoire vectoriel
msg.msg_iovlen = 3; // nb elements de msg_iov
// printf("Sending message of %d+2 bytes\n", size);
ret = rt_dev_sendmsg(sock, &msg, 0);
if (ret == -EBADF)
return ret;
else if (ret != (int)(sizeof(nbmsg) + sizeof(msgsize) + data_size)) {
printf("*** Error *** rt_dev_sendmsg() = %d : %s\n",
ret, strerror(-ret));
return ret;
}/* else {
printf("*** Debug ***data emit ok\n");
}*/
return 0;
}
int recv_data()
{
int ret,i;
struct msghdr msg;
struct iovec iov[3];
unsigned short msgsize = data_size;
unsigned short nbmsg = nb_data;
struct sockaddr_in addr;
for (i=0;i<nb_data;i++) {
iov[0].iov_base = &msgsize;
iov[0].iov_len = sizeof(msgsize);
iov[1].iov_base = buffer_in;
iov[1].iov_len = data_size;
iov[2].iov_base = &nbmsg;
iov[2].iov_len = sizeof(nbmsg);
memset(&msg, 0, sizeof(msg));
msg.msg_name = &addr;
msg.msg_namelen = sizeof(addr);
msg.msg_iov = iov;
msg.msg_iovlen = 3;
ret = rt_dev_recvmsg(sock, &msg, 0);
if (ret <= 0) {
printf("*** Error *** rt_dev_recvmsg() = %d : %s\n",
ret, strerror(-ret));
return ret;
} /*else {
unsigned long ip = ntohl(addr.sin_addr.s_addr);
printf("receive data OK\n");
// printf("received packet from %lu.%lu.%lu.%lu, length: %zd+2, "
// "encoded length: %d,\n flags: %X, content
%s\n", ip >> 24,
// (ip >> 16) & 0xFF, (ip >> 8) & 0xFF, ip & 0xFF,
// ret-sizeof(msgsize), msgsize, msg.msg_flags,
// (memcmp(buffer_in, buffer_out, ret-sizeof(msgsize)) == 0) ?
// "ok" : "corrupted");
}*/
}
return 0;
}
void catch_signal(int sig)
{
//rt_task_suspend(&rt_rsg_task);
}
void perform_remote(void *arg)
{
unsigned int i = 0;
while(1) {
//printf("\nPass %d",i++);
if(recv_data()) continue;
if(xmit_data()) continue;
}
}
int main(int argc, char *argv[])
{
int ret;
unsigned int i;
struct sockaddr_in local_addr;
struct in_addr dest_ip;
while (1) {
switch (getopt(argc, argv, "d:")) {
case 'd':
dest_ip_s = optarg;
break;
case -1:
goto end_of_opt;
default:
printf("usage: %s [-d <dest_ip>]\n", argv[0]);
return 0;
}
}
end_of_opt:
inet_aton(dest_ip_s, &dest_ip);
signal(SIGTERM, catch_signal);
signal(SIGINT, catch_signal);
signal(SIGHUP, catch_signal);
mlockall(MCL_CURRENT|MCL_FUTURE);
printf("destination ip address %s=%08x\n", dest_ip_s, dest_ip.s_addr);
printf("size %d\n", data_size);
/* fill output buffer with test pattern */
for (i = 0; i < sizeof(buffer_out); i++)
buffer_out[i] = i & 0xFF;
/* create rt-socket */
sock = rt_dev_socket(AF_INET,SOCK_DGRAM,0);
if (sock < 0) {
printf("*** Error *** rt_dev_socket() = %d!\n", sock);
return sock;
}
/* extend the socket pool */
ret = rt_dev_ioctl(sock, RTNET_RTIOC_EXTPOOL, &add_rtskbs);
if (ret != (int)add_rtskbs) {
printf("*** Error *** rt_dev_ioctl(RT_IOC_SO_EXTPOOL) = %d\n",
ret);
rt_dev_close(sock);
return -1;
}
// /* reception acquitement bloquant + timeout */
// ret = rt_dev_ioctl(sock, RTNET_RTIOC_TIMEOUT, &recv_timeout);
// if (ret != 0) {
// printf("Error rt_dev_ioctl(RT_IOC_TIME_OUT) = %d\n", ret);
// rt_dev_close(sock);
// return -1;
// }
/* bind the rt-socket to a port */
memset(&local_addr, 0, sizeof(struct sockaddr_in));
local_addr.sin_family = AF_INET;
local_addr.sin_port = htons(PORT);
local_addr.sin_addr.s_addr = INADDR_ANY;
ret = rt_dev_bind(sock, (struct sockaddr *)&local_addr,
sizeof(struct sockaddr_in));
if (ret < 0) {
printf("*** Error *** rt_dev_bind() = %d!\n", ret);
rt_dev_close(sock);
return ret;
}
/* set destination address */
memset(&dest_addr, 0, sizeof(struct sockaddr_in));
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(PORT);
dest_addr.sin_addr = dest_ip;
ret = rt_task_create(&rt_rsg_task, "REMOTE", 0, 10, 0);
if (ret != 0) {
printf(" rt_task_create(recv) = %d!\n", ret);
rt_dev_close(sock);
return ret;
}
rt_task_start(&rt_rsg_task, perform_remote, NULL);
pause();
/* Note: The following loop and the strict ordering "close before task
* termination" is no longer required since Xenomai 2.4. */
while (rt_dev_close(sock) == -EAGAIN) {
printf("Socket busy - waiting...\n");
sleep(1);
}
rt_task_delete(&rt_rsg_task);
return 0;
}
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