lload for xenix
Sandford Zelkovitz
sandy at conexch.UUCP
Sat May 27 16:13:07 AEST 1989
Below, is my ported version of lload.c for Xenix. The original code,
by Lars Pensj from Myab Gothenburg, Sweden, was distributed in
alt.sources.
--------------------------- cut for lload.c ----------------------------
/*
* Load Average deamon.
*
* The load average is updated every constant time interval, and the result
* written to a file as 3 double values.
*
* The load average is for the last 1, 5 and 15 minutes (3 values).
*
* A second argument (-v) will set the program in a verbose mode, writing
* the load average to the standard output and not to the file.
*
* Preferably start this process from the inittab. It needs special
* priviledges to read from /dev/kmem.
*
* The following processes are regarded as "runnning":
* A process that has the SRUN status (simply running).
* A process that is being created (SIDLE).
* A process that is being swapped out (SXBRK).
* A process that waits for disk I/O.
*
* A process is regarded as waiting for disk I/O if it is SSLEEP and
* has wchan set to a buf in the buffer pool.
*
* The sleep is implemented using poll on a stream device, not the
* more usual sleep() call. Why ?
* Because you do not want to wake up simultaneosly with other programs
* doing sleep(), which might give wrong load average.
* Of course, if you do not have the stream pipe device, use the normal
* sleep().
*/
/* For Xenix: compile as follows: cc -Ox lload.c -lm -lx -o lload */
/* Modified for Xenix by Sanford Zelkovitz XBBS 714-898-8634 */
#include <fcntl.h>
#ifdef M_XENIX
#include <sys/a.out.h>
#else
#include <nlist.h>
#endif
#include <stdio.h>
#include <stropts.h>
#include <poll.h>
#include <math.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/buf.h>
#ifdef M_XENIX
#include <sys/page.h>
#else
#include <sys/immu.h>
#include <sys/region.h>
#endif
#include <sys/var.h>
#include <sys/proc.h>
/* #define DEBUG */ /* Will append all values in a debug file */
#define LOADAV "/etc/loadav" /* Where to write the load avarge */
#define STREAM_PIPE "/dev/spx" /* Used for polling with timeout */
/*
* You may or may not need the '_' in the following names.
*/
#define VAR_NAME "_v"
#ifdef M_I386
#define BUF_NAME "_pbuf"
#else
#define BUF_NAME "_buf"
#endif
#define PROC_NAME "_proc"
struct nlist nl[] = {
{VAR_NAME},
{BUF_NAME},
{PROC_NAME},
{0},
};
int loadfile; /* file descr to result file */
struct proc *p;
struct var v;
int kmem;
struct nlist *v_p, *proc_p, *buf_p;
int size;
int first_buf, last_buf;
int sleeping = 1; /* Poll frequency in seconds */
int verbose = 0;
double av[3] = { 0.0, 0.0, 0.0 }; /* The loadaverage */
double apa[3]; /* Holding constants */
main(argc, argv)
char **argv;
{
int i, n, n_run, n_disk;
#ifdef DEBUG
int debug_fd;
char buff[100];
debug_fd = open("/tmp/loadavdebug", O_CREAT|O_WRONLY);
#endif
if (argc == 2 && strcmp(argv[1], "-v") == 0) {
verbose = 1;
printf("Verbose\n");
}
kmem = open("/dev/kmem", 0);
if (kmem == -1) {
perror("/dev/kmem");
exit(1);
}
if (!verbose) {
loadfile = open(LOADAV, 1|O_CREAT,0664);
if (loadfile == -1) {
fprintf(stderr, "%s:", argv[0]);
perror(LOADAV);
exit(1);
}
}
#ifdef M_XENIX
if (nlist("/xenix", nl) == -1) {
#else
if (nlist("/unix", nl) == -1) {
#endif
perror("nlist");
exit(1);
}
for (i=0; nl[i].n_name; i++) {
#ifdef M_XENIX
if(nl[i].n_name[0] == '\0')
break;
#endif
#ifdef DEBUG
fprintf(stderr, "nl[%d] = %s\n", i, nl[i].n_name);
#endif
if (nl[i].n_value == 0) {
fprintf(stderr, "Could not get address for %s\n", nl[i].n_name);
exit(1);
}
if (strcmp(nl[i].n_name, VAR_NAME) == 0)
v_p = &nl[i];
if (strcmp(nl[i].n_name, PROC_NAME) == 0)
proc_p = &nl[i];
if (strcmp(nl[i].n_name, BUF_NAME) == 0)
buf_p = &nl[i];
}
/*
* Setup the constants used for computing load average.
*/
apa[0] = exp(-sleeping/60.0);
apa[1] = exp(-sleeping/300.0);
apa[2] = exp(-sleeping/900.0);
/*
* Start looping
*/
while(1) {
/*
* Read the 'v' structure every time. It says how
* many procs are used.
*/
if (lseek(kmem, v_p->n_value, 0) == -1) {
perror("lseek v");
exit(1);
}
if (read(kmem, &v, sizeof v) == -1) {
perror("read v");
exit(1);
}
size = (struct proc *)v.ve_proc - (struct proc *)proc_p->n_value;
first_buf = buf_p->n_value;
last_buf = first_buf + v.v_buf * sizeof (struct buf);
if (lseek(kmem, proc_p->n_value, 0) == -1) {
perror("lseek proc");
exit(1);
}
p = (struct proc *)malloc(size * sizeof (struct proc));
if (p == 0) {
fprintf(stderr, "Could not malloc %d bytes\n",
size * sizeof (struct proc));
exit(1);
}
n = read(kmem, p, size * sizeof (struct proc));
if (n != size * sizeof (struct proc)) {
if (n == -1) {
perror("read procs");
exit(1);
}
fprintf(stderr, "Could only read %d (%d) procs\n",
n, size);
size = n / sizeof (struct proc);
}
n_run = 0;
n_disk = 0;
for (i=0; i<size; i++) {
if (p[i].p_stat == SRUN || p[i].p_stat == SIDL ||
p[i].p_stat == SXBRK)
n_run++;
else if (p[i].p_stat == SSLEEP &&
(unsigned int)p[i].p_wchan >= first_buf &&
(unsigned int)p[i].p_wchan < last_buf)
n_disk++;
}
/*
* Update the load average using a decay filter.
*/
for (i = 0; i < 3; i++)
av[i] = apa[i] * av[i] + (n_run + n_disk) * (1.0 - apa[i]);
if (!verbose) {
if (lseek(loadfile, 0L, 0) == -1) {
fprintf(stderr, "Couldn't seek in %s\n", LOADAV);
exit(1);
}
if (write(loadfile, (char *)av, sizeof av) != sizeof av) {
perror(argv[0]);
exit(1);
}
} else
printf("(%d %d) %f %f %f\n", n_run, n_disk,
av[0], av[1], av[2]);
#ifdef DEBUG
sprintf(buff, "(%d %d) %4.2f\n", n_run, n_disk,
av[0]);
write(debug_fd, buff, strlen(buff));
#endif
(void)nap(sleeping * 1000);
free(p);
}
}
#ifndef M_XENIX
/*
* Use a stream pipe to implement a sleep.
* We have a stream pipe for ourselves, so we know noone will write
* on it.
*/
nap(milli) {
static int fd = 0;
static struct pollfd pollfd;
if (fd == 0) {
fd = open(STREAM_PIPE, 0);
if (fd == -1) {
perror(STREAM_PIPE);
exit(1);
}
pollfd.fd = fd;
pollfd.events = POLLIN;
}
if (poll(&pollfd, 1, milli) == -1) {
perror("nap: poll");
exit(1);
}
if (pollfd.revents != 0) {
fprintf(stderr, "nap: poll: got something\n");
exit(1);
}
}
#endif
More information about the Alt.sources
mailing list