/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93 */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #ifdef GPROF #include #include #undef MCOUNT static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); static void kmstartup(void *); SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL); struct gmonparam _gmonparam = { GMON_PROF_OFF }; #ifdef GUPROF void nullfunc_loop_profiled() { int i; for (i = 0; i < CALIB_SCALE; i++) nullfunc_profiled(); } #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ void nullfunc_profiled() { } #endif /* GUPROF */ /* * Update the histograms to support extending the text region arbitrarily. * This is done slightly naively (no sparse regions), so will waste slight * amounts of memory, but will overall work nicely enough to allow profiling * of KLDs. */ void kmupetext(uintfptr_t nhighpc) { struct gmonparam np; /* slightly large */ struct gmonparam *p = &_gmonparam; char *cp; GIANT_REQUIRED; bcopy(p, &np, sizeof(*p)); np.highpc = ROUNDUP(nhighpc, HISTFRACTION * sizeof(HISTCOUNTER)); if (np.highpc <= p->highpc) return; np.textsize = np.highpc - p->lowpc; np.kcountsize = np.textsize / HISTFRACTION; np.hashfraction = HASHFRACTION; np.fromssize = np.textsize / HASHFRACTION; np.tolimit = np.textsize * ARCDENSITY / 100; if (np.tolimit < MINARCS) np.tolimit = MINARCS; else if (np.tolimit > MAXARCS) np.tolimit = MAXARCS; np.tossize = np.tolimit * sizeof(struct tostruct); cp = malloc(np.kcountsize + np.fromssize + np.tossize, M_GPROF, M_WAITOK); /* * Check for something else extending highpc while we slept. */ if (np.highpc <= p->highpc) { free(cp, M_GPROF); return; } np.tos = (struct tostruct *)cp; cp += np.tossize; np.kcount = (HISTCOUNTER *)cp; cp += np.kcountsize; np.froms = (u_short *)cp; #ifdef GUPROF /* Reinitialize pointers to overhead counters. */ np.cputime_count = &KCOUNT(&np, PC_TO_I(&np, cputime)); np.mcount_count = &KCOUNT(&np, PC_TO_I(&np, mcount)); np.mexitcount_count = &KCOUNT(&np, PC_TO_I(&np, mexitcount)); #endif critical_enter(); bcopy(p->tos, np.tos, p->tossize); bzero((char *)np.tos + p->tossize, np.tossize - p->tossize); bcopy(p->kcount, np.kcount, p->kcountsize); bzero((char *)np.kcount + p->kcountsize, np.kcountsize - p->kcountsize); bcopy(p->froms, np.froms, p->fromssize); bzero((char *)np.froms + p->fromssize, np.fromssize - p->fromssize); cp = (char *)p->tos; bcopy(&np, p, sizeof(*p)); critical_exit(); free(cp, M_GPROF); } static void kmstartup(void *dummy) { char *cp; struct gmonparam *p = &_gmonparam; #ifdef GUPROF int cputime_overhead; int empty_loop_time; int i; int mcount_overhead; int mexitcount_overhead; int nullfunc_loop_overhead; int nullfunc_loop_profiled_time; uintfptr_t tmp_addr; #endif /* * 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((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER)); p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER)); p->textsize = p->highpc - p->lowpc; printf("Profiling kernel, textsize=%lu [%jx..%jx]\n", p->textsize, (uintmax_t)p->lowpc, (uintmax_t)p->highpc); 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 = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, M_GPROF, M_WAITOK | M_ZERO); p->tos = (struct tostruct *)cp; cp += p->tossize; p->kcount = (HISTCOUNTER *)cp; cp += p->kcountsize; p->froms = (u_short *)cp; p->histcounter_type = FUNCTION_ALIGNMENT / HISTFRACTION * NBBY; #ifdef GUPROF /* Signed counters. */ p->histcounter_type = -p->histcounter_type; /* Initialize pointers to overhead counters. */ p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime)); p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount)); p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount)); /* * Disable interrupts to avoid interference while we calibrate * things. */ critical_enter(); /* * Determine overheads. * XXX this needs to be repeated for each useful timer/counter. */ cputime_overhead = 0; startguprof(p); for (i = 0; i < CALIB_SCALE; i++) cputime_overhead += cputime(); empty_loop(); startguprof(p); empty_loop(); empty_loop_time = cputime(); nullfunc_loop_profiled(); /* * Start profiling. There won't be any normal function calls since * interrupts are disabled, but we will call the profiling routines * directly to determine their overheads. */ p->state = GMON_PROF_HIRES; startguprof(p); nullfunc_loop_profiled(); startguprof(p); for (i = 0; i < CALIB_SCALE; i++) MCOUNT_OVERHEAD(sys_profil); mcount_overhead = KCOUNT(p, PC_TO_I(p, sys_profil)); startguprof(p); for (i = 0; i < CALIB_SCALE; i++) MEXITCOUNT_OVERHEAD(); MEXITCOUNT_OVERHEAD_GETLABEL(tmp_addr); mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); p->state = GMON_PROF_OFF; stopguprof(p); critical_exit(); nullfunc_loop_profiled_time = 0; for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled; tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end; tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER)) nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr)); #define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE) #define c2n(count, freq) ((int)((count) * 1000000000LL / freq)) printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n", CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)), CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)), CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)), CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)), CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate))); cputime_overhead -= empty_loop_time; mcount_overhead -= empty_loop_time; mexitcount_overhead -= empty_loop_time; /*- * Profiling overheads are determined by the times between the * following events: * MC1: mcount() is called * MC2: cputime() (called from mcount()) latches the timer * MC3: mcount() completes * ME1: mexitcount() is called * ME2: cputime() (called from mexitcount()) latches the timer * ME3: mexitcount() completes. * The times between the events vary slightly depending on instruction * combination and cache misses, etc. Attempt to determine the * minimum times. These can be subtracted from the profiling times * without much risk of reducing the profiling times below what they * would be when profiling is not configured. Abbreviate: * ab = minimum time between MC1 and MC3 * a = minimum time between MC1 and MC2 * b = minimum time between MC2 and MC3 * cd = minimum time between ME1 and ME3 * c = minimum time between ME1 and ME2 * d = minimum time between ME2 and ME3. * These satisfy the relations: * ab <= mcount_overhead (just measured) * a + b <= ab * cd <= mexitcount_overhead (just measured) * c + d <= cd * a + d <= nullfunc_loop_profiled_time (just measured) * a >= 0, b >= 0, c >= 0, d >= 0. * Assume that ab and cd are equal to the minimums. */ p->cputime_overhead = CALIB_DOSCALE(cputime_overhead); p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead); p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead - cputime_overhead); nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time; p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead - nullfunc_loop_overhead) / 4); p->mexitcount_pre_overhead = p->mexitcount_overhead + p->cputime_overhead - p->mexitcount_post_overhead; p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead) - p->mexitcount_post_overhead; p->mcount_post_overhead = p->mcount_overhead + p->cputime_overhead - p->mcount_pre_overhead; printf( "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n", c2n(p->cputime_overhead, p->profrate), c2n(p->mcount_overhead, p->profrate), c2n(p->mcount_pre_overhead, p->profrate), c2n(p->mcount_post_overhead, p->profrate), c2n(p->cputime_overhead, p->profrate), c2n(p->mexitcount_overhead, p->profrate), c2n(p->mexitcount_pre_overhead, p->profrate), c2n(p->mexitcount_post_overhead, p->profrate)); printf( "Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n", p->cputime_overhead, p->mcount_overhead, p->mcount_pre_overhead, p->mcount_post_overhead, p->cputime_overhead, p->mexitcount_overhead, p->mexitcount_pre_overhead, p->mexitcount_post_overhead); #endif /* GUPROF */ } /* * Return kernel profiling information. */ static int sysctl_kern_prof(SYSCTL_HANDLER_ARGS) { int *name = (int *) arg1; u_int namelen = arg2; struct gmonparam *gp = &_gmonparam; int error; int state; /* all sysctl names at this level are terminal */ if (namelen != 1) return (ENOTDIR); /* overloaded */ switch (name[0]) { case GPROF_STATE: state = gp->state; error = sysctl_handle_int(oidp, &state, 0, req); if (error) return (error); if (!req->newptr) return (0); if (state == GMON_PROF_OFF) { gp->state = state; PROC_LOCK(&proc0); stopprofclock(&proc0); PROC_UNLOCK(&proc0); stopguprof(gp); } else if (state == GMON_PROF_ON) { gp->state = GMON_PROF_OFF; stopguprof(gp); gp->profrate = profhz; PROC_LOCK(&proc0); startprofclock(&proc0); PROC_UNLOCK(&proc0); gp->state = state; #ifdef GUPROF } else if (state == GMON_PROF_HIRES) { gp->state = GMON_PROF_OFF; PROC_LOCK(&proc0); stopprofclock(&proc0); PROC_UNLOCK(&proc0); startguprof(gp); gp->state = state; #endif } else if (state != gp->state) return (EINVAL); return (0); case GPROF_COUNT: return (sysctl_handle_opaque(oidp, gp->kcount, gp->kcountsize, req)); case GPROF_FROMS: return (sysctl_handle_opaque(oidp, gp->froms, gp->fromssize, req)); case GPROF_TOS: return (sysctl_handle_opaque(oidp, gp->tos, gp->tossize, req)); case GPROF_GMONPARAM: return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req)); default: return (EOPNOTSUPP); } /* NOTREACHED */ } static SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW | CTLFLAG_MPSAFE, sysctl_kern_prof, ""); #endif /* GPROF */ /* * Profiling system call. * * The scale factor is a fixed point number with 16 bits of fraction, so that * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. */ #ifndef _SYS_SYSPROTO_H_ struct profil_args { caddr_t samples; size_t size; size_t offset; u_int scale; }; #endif /* ARGSUSED */ int sys_profil(struct thread *td, struct profil_args *uap) { struct uprof *upp; struct proc *p; if (uap->scale > (1 << 16)) return (EINVAL); p = td->td_proc; if (uap->scale == 0) { PROC_LOCK(p); stopprofclock(p); PROC_UNLOCK(p); return (0); } PROC_LOCK(p); upp = &td->td_proc->p_stats->p_prof; PROC_PROFLOCK(p); upp->pr_off = uap->offset; upp->pr_scale = uap->scale; upp->pr_base = uap->samples; upp->pr_size = uap->size; PROC_PROFUNLOCK(p); startprofclock(p); PROC_UNLOCK(p); return (0); } /* * Scale is a fixed-point number with the binary point 16 bits * into the value, and is <= 1.0. pc is at most 32 bits, so the * intermediate result is at most 48 bits. */ #define PC_TO_INDEX(pc, prof) \ ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) /* * Collect user-level profiling statistics; called on a profiling tick, * when a process is running in user-mode. This routine may be called * from an interrupt context. We perform the update with an AST * that will vector us to trap() with a context in which copyin and * copyout will work. Trap will then call addupc_task(). * * Note that we may (rarely) not get around to the AST soon enough, and * lose profile ticks when the next tick overwrites this one, but in this * case the system is overloaded and the profile is probably already * inaccurate. */ void addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks) { struct uprof *prof; if (ticks == 0) return; prof = &td->td_proc->p_stats->p_prof; PROC_PROFLOCK(td->td_proc); if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) { PROC_PROFUNLOCK(td->td_proc); return; /* out of range; ignore */ } PROC_PROFUNLOCK(td->td_proc); td->td_profil_addr = pc; td->td_profil_ticks = ticks; td->td_pflags |= TDP_OWEUPC; thread_lock(td); td->td_flags |= TDF_ASTPENDING; thread_unlock(td); } /* * Actually update the profiling statistics. If the update fails, we * simply turn off profiling. */ void addupc_task(struct thread *td, uintfptr_t pc, u_int ticks) { struct proc *p = td->td_proc; struct uprof *prof; caddr_t addr; u_int i; u_short v; int stop = 0; if (ticks == 0) return; PROC_LOCK(p); if (!(p->p_flag & P_PROFIL)) { PROC_UNLOCK(p); return; } p->p_profthreads++; prof = &p->p_stats->p_prof; PROC_PROFLOCK(p); if (pc < prof->pr_off || (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { PROC_PROFUNLOCK(p); goto out; } addr = prof->pr_base + i; PROC_PROFUNLOCK(p); PROC_UNLOCK(p); if (copyin(addr, &v, sizeof(v)) == 0) { v += ticks; if (copyout(&v, addr, sizeof(v)) == 0) { PROC_LOCK(p); goto out; } } stop = 1; PROC_LOCK(p); out: if (--p->p_profthreads == 0) { if (p->p_flag & P_STOPPROF) { wakeup(&p->p_profthreads); p->p_flag &= ~P_STOPPROF; stop = 0; } } if (stop) stopprofclock(p); PROC_UNLOCK(p); }