usr/src/lib/libc/gmon/gmon.c

/*-
 * Copyright (c) 1983, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#if !defined(lint) && defined(LIBC_SCCS)
static char sccsid[] = "@(#)gmon.c      8.1 (Berkeley) %G%";
#endif

#include <sys/param.h>
#include <sys/time.h>
#include <sys/gmon.h>
#include <sys/sysctl.h>

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

extern char *minbrk asm ("minbrk");

struct gmonparam _gmonparam = { GMON_PROF_OFF };

static int      s_scale;
/* see profil(2) where this is describe (incorrectly) */
#define         SCALE_1_TO_1    0x10000L

#define ERR(s) write(2, s, sizeof(s))

void    moncontrol __P((int));
static int hertz __P((void));

void
monstartup(lowpc, highpc)
        u_long lowpc;
        u_long highpc;
{
        register int o;
        char *cp;
        struct gmonparam *p = &_gmonparam;

        /*
         * round lowpc and highpc to multiples of the density we're using
         * so the rest of the scaling (here and in gprof) stays in ints.
         */
        p->lowpc = ROUNDDOWN(lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
        p->highpc = ROUNDUP(highpc, HISTFRACTION * sizeof(HISTCOUNTER));
        p->textsize = p->highpc - p->lowpc;
        p->kcountsize = p->textsize / HISTFRACTION;
        p->hashfraction = HASHFRACTION;
        p->fromssize = p->textsize / HASHFRACTION;
        p->tolimit = p->textsize * ARCDENSITY / 100;
        if (p->tolimit < MINARCS)
                p->tolimit = MINARCS;
        else if (p->tolimit > MAXARCS)
                p->tolimit = MAXARCS;
        p->tossize = p->tolimit * sizeof(struct tostruct);

        cp = sbrk(p->kcountsize + p->fromssize + p->tossize);
        if (cp == (char *)-1) {
                ERR("monstartup: out of memory\n");
                return;
        }
#ifdef notdef
        bzero(cp, p->kcountsize + p->fromssize + p->tossize);
#endif
        p->tos = (struct tostruct *)cp;
        cp += p->tossize;
        p->kcount = (u_short *)cp;
        cp += p->kcountsize;
        p->froms = (u_short *)cp;

        minbrk = sbrk(0);
        p->tos[0].link = 0;

        o = p->highpc - p->lowpc;
        if (p->kcountsize < o) {
#ifndef hp300
                s_scale = ((float)p->kcountsize / o ) * SCALE_1_TO_1;
#else /* avoid floating point */
                int quot = o / p->kcountsize;

                if (quot >= 0x10000)
                        s_scale = 1;
                else if (quot >= 0x100)
                        s_scale = 0x10000 / quot;
                else if (o >= 0x800000)
                        s_scale = 0x1000000 / (o / (p->kcountsize >> 8));
                else
                        s_scale = 0x1000000 / ((o << 8) / p->kcountsize);
#endif
        } else
                s_scale = SCALE_1_TO_1;

        moncontrol(1);
}

void
_mcleanup()
{
        int fd;
        int fromindex;
        int endfrom;
        u_long frompc;
        int toindex;
        struct rawarc rawarc;
        struct gmonparam *p = &_gmonparam;
        struct gmonhdr gmonhdr, *hdr;
        struct clockinfo clockinfo;
        int mib[2];
        size_t size;
#ifdef DEBUG
        int log, len;
        char buf[200];
#endif

        if (p->state == GMON_PROF_ERROR)
                ERR("_mcleanup: tos overflow\n");

        size = sizeof(clockinfo);
        mib[0] = CTL_KERN;
        mib[1] = KERN_CLOCKRATE;
        if (sysctl(mib, 2, &clockinfo, &size, NULL, 0) < 0) {
                /*
                 * Best guess
                 */
                clockinfo.profhz = hertz();
        } else if (clockinfo.profhz == 0) {
                if (clockinfo.hz != 0)
                        clockinfo.profhz = clockinfo.hz;
                else
                        clockinfo.profhz = hertz();
        }

        moncontrol(0);
        fd = open("gmon.out", O_CREAT|O_TRUNC|O_WRONLY, 0666);
        if (fd < 0) {
                perror("mcount: gmon.out");
                return;
        }
#ifdef DEBUG
        log = open("gmon.log", O_CREAT|O_TRUNC|O_WRONLY, 0664);
        if (log < 0) {
                perror("mcount: gmon.log");
                return;
        }
        len = sprintf(buf, "[mcleanup1] kcount 0x%x ssiz %d\n",
            p->kcount, p->kcountsize);
        write(log, buf, len);
#endif
        hdr = (struct gmonhdr *)&gmonhdr;
        hdr->lpc = p->lowpc;
        hdr->hpc = p->highpc;
        hdr->ncnt = p->kcountsize + sizeof(gmonhdr);
        hdr->version = GMONVERSION;
        hdr->profrate = clockinfo.profhz;
        write(fd, (char *)hdr, sizeof *hdr);
        write(fd, p->kcount, p->kcountsize);
        endfrom = p->fromssize / sizeof(*p->froms);
        for (fromindex = 0; fromindex < endfrom; fromindex++) {
                if (p->froms[fromindex] == 0)
                        continue;

                frompc = p->lowpc;
                frompc += fromindex * p->hashfraction * sizeof(*p->froms);
                for (toindex = p->froms[fromindex]; toindex != 0;
                     toindex = p->tos[toindex].link) {
#ifdef DEBUG
                        len = sprintf(buf,
                        "[mcleanup2] frompc 0x%x selfpc 0x%x count %d\n" ,
                                frompc, p->tos[toindex].selfpc,
                                p->tos[toindex].count);
                        write(log, buf, len);
#endif
                        rawarc.raw_frompc = frompc;
                        rawarc.raw_selfpc = p->tos[toindex].selfpc;
                        rawarc.raw_count = p->tos[toindex].count;
                        write(fd, &rawarc, sizeof rawarc);
                }
        }
        close(fd);
}

/*
 * Control profiling
 *      profiling is what mcount checks to see if
 *      all the data structures are ready.
 */
void
moncontrol(mode)
        int mode;
{
        struct gmonparam *p = &_gmonparam;

        if (mode) {
                /* start */
                profil((char *)p->kcount, p->kcountsize, (int)p->lowpc,
                    s_scale);
                p->state = GMON_PROF_ON;
        } else {
                /* stop */
                profil((char *)0, 0, 0, 0);
                p->state = GMON_PROF_OFF;
        }
}

/*
 * discover the tick frequency of the machine
 * if something goes wrong, we return 0, an impossible hertz.
 */
static int
hertz()
{
        struct itimerval tim;

        tim.it_interval.tv_sec = 0;
        tim.it_interval.tv_usec = 1;
        tim.it_value.tv_sec = 0;
        tim.it_value.tv_usec = 0;
        setitimer(ITIMER_REAL, &tim, 0);
        setitimer(ITIMER_REAL, 0, &tim);
        if (tim.it_interval.tv_usec < 2)
                return(0);
        return (1000000 / tim.it_interval.tv_usec);
}