diff options
Diffstat (limited to 'sys/kern/subr_prof.c')
| -rw-r--r-- | sys/kern/subr_prof.c | 589 |
1 files changed, 589 insertions, 0 deletions
diff --git a/sys/kern/subr_prof.c b/sys/kern/subr_prof.c new file mode 100644 index 0000000..c5b6b08 --- /dev/null +++ b/sys/kern/subr_prof.c @@ -0,0 +1,589 @@ +/*- + * 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. + * 4. 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 <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/sysproto.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/proc.h> +#include <sys/resourcevar.h> +#include <sys/sysctl.h> + +#include <machine/cpu.h> + +#ifdef GPROF +#include <sys/malloc.h> +#include <sys/gmon.h> +#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(dummy) + 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 = 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; + 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, 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_SLOCK(p); + upp->pr_off = uap->offset; + upp->pr_scale = uap->scale; + upp->pr_base = uap->samples; + upp->pr_size = uap->size; + PROC_SUNLOCK(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 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(). + * + * 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; + caddr_t addr; + u_int i; + int v; + + if (ticks == 0) + return; + prof = &td->td_proc->p_stats->p_prof; + PROC_SLOCK(td->td_proc); + if (pc < prof->pr_off || + (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { + PROC_SUNLOCK(td->td_proc); + return; /* out of range; ignore */ + } + + addr = prof->pr_base + i; + PROC_SUNLOCK(td->td_proc); + if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) { + 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); + } +} + +/* + * Much like before, but we can afford to take faults here. 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_SLOCK(p); + if (pc < prof->pr_off || + (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { + PROC_SUNLOCK(p); + goto out; + } + + addr = prof->pr_base + i; + PROC_SUNLOCK(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); + stop = 0; + } + } + if (stop) + stopprofclock(p); + PROC_UNLOCK(p); +} + +#if (defined(__amd64__) || defined(__i386__)) && \ + defined(__GNUCLIKE_CTOR_SECTION_HANDLING) +/* + * Support for "--test-coverage --profile-arcs" in GCC. + * + * We need to call all the functions in the .ctor section, in order + * to get all the counter-arrays strung into a list. + * + * XXX: the .ctors call __bb_init_func which is located in over in + * XXX: i386/i386/support.s for historical reasons. There is probably + * XXX: no reason for that to be assembler anymore, but doing it right + * XXX: in MI C code requires one to reverse-engineer the type-selection + * XXX: inside GCC. Have fun. + * + * XXX: Worrisome perspective: Calling the .ctors may make C++ in the + * XXX: kernel feasible. Don't. + */ +typedef void (*ctor_t)(void); +extern ctor_t _start_ctors, _stop_ctors; + +static void +tcov_init(void *foo __unused) +{ + ctor_t *p, q; + + for (p = &_start_ctors; p < &_stop_ctors; p++) { + q = *p; + q(); + } +} + +SYSINIT(tcov_init, SI_SUB_KPROF, SI_ORDER_SECOND, tcov_init, NULL); + +/* + * GCC contains magic to recognize calls to for instance execve() and + * puts in calls to this function to preserve the profile counters. + * XXX: Put zinging punchline here. + */ +void __bb_fork_func(void); +void +__bb_fork_func(void) +{ +} + +#endif + |
