/*- * 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 * $FreeBSD: src/sys/kern/subr_prof.c,v 1.32.2.2 2000/08/03 00:09:32 ps Exp $ */ #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 #include void nullfunc_loop_profiled(void) { int i; for (i = 0; i < CALIB_SCALE; i++) nullfunc_profiled(); } #define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */ void nullfunc_profiled(void) { } #endif /* GUPROF */ 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; kprintf("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 *)kmalloc(p->kcountsize + p->fromssize + p->tossize, M_GPROF, M_NOWAIT | M_ZERO); if (cp == NULL) { kprintf("No memory for profiling.\n"); return; } p->tos = (struct tostruct *)cp; cp += p->tossize; p->kcount = (HISTCOUNTER *)cp; cp += p->kcountsize; p->froms = (u_short *)cp; #ifdef GUPROF /* 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. */ cpu_disable_intr(); /* * 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++) #if defined(__i386__) && __GNUC__ >= 2 __asm("pushl %0; call __mcount; popl %%ecx" : : "i" (profil) : "ax", "bx", "cx", "dx", "memory"); #else #error #endif mcount_overhead = KCOUNT(p, PC_TO_I(p, profil)); startguprof(p); for (i = 0; i < CALIB_SCALE; i++) #if defined(__i386__) && __GNUC__ >= 2 __asm("call " __XSTRING(HIDENAME(mexitcount)) "; 1:" : : : "ax", "bx", "cx", "dx", "memory"); __asm("movl $1b,%0" : "=rm" (tmp_addr)); #else #error #endif mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr)); p->state = GMON_PROF_OFF; stopguprof(p); cpu_enable_intr(); 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)) kprintf("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 = minumum 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; kprintf( "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)); kprintf( "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); lwkt_gettoken(&proc0.p_token); if (state == GMON_PROF_OFF) { gp->state = state; stopprofclock(&proc0); stopguprof(gp); } else if (state == GMON_PROF_ON) { gp->state = GMON_PROF_OFF; stopguprof(gp); gp->profrate = profhz; startprofclock(&proc0); gp->state = state; #ifdef GUPROF } else if (state == GMON_PROF_HIRES) { gp->state = GMON_PROF_OFF; stopprofclock(&proc0); startguprof(gp); gp->state = state; #endif } else if (state != gp->state) { error = EINVAL; } lwkt_reltoken(&proc0.p_token); return (error); 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 */ } SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, 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. * * MPALMOSTSAFE */ int sys_profil(struct profil_args *uap) { struct proc *p = curproc; struct uprof *upp; if (uap->scale > (1 << 16)) return (EINVAL); get_mplock(); if (uap->scale == 0) { stopprofclock(p); } else { upp = &p->p_prof; /* Block profile interrupts while changing state. */ crit_enter(); upp->pr_off = uap->offset; upp->pr_scale = uap->scale; upp->pr_base = uap->samples; upp->pr_size = uap->size; startprofclock(p); crit_exit(); } rel_mplock(); 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 try to update the user profiling buffers * cheaply with fuswintr() and suswintr(). If that fails, we revert to * an AST that will vector us to trap() with a context in which copyin * and copyout will work. Trap will then call addupc_task(). * * XXX fuswintr() and suswintr() never worked (always returnde -1), remove * them. It's just a bad idea to try to do this from a hard interrupt. * * 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 proc *p, u_long pc, u_int ticks) { struct uprof *prof; u_int i; if (ticks == 0) return; prof = &p->p_prof; if (pc < prof->pr_off || (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) return; /* out of range; ignore */ prof->pr_addr = pc; prof->pr_ticks = ticks; need_proftick(); } /* * Much like before, but we can afford to take faults here. If the * update fails, we simply turn off profiling. */ void addupc_task(struct proc *p, u_long pc, u_int ticks) { struct uprof *prof; caddr_t addr; u_int i; u_short v; /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ if ((p->p_flags & P_PROFIL) == 0 || ticks == 0) return; prof = &p->p_prof; if (pc < prof->pr_off || (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) return; addr = prof->pr_base + i; if (copyin(addr, (caddr_t)&v, sizeof(v)) == 0) { v += ticks; if (copyout((caddr_t)&v, addr, sizeof(v)) == 0) return; } stopprofclock(p); }