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31 * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sysproto.h>
40 #include <sys/kernel.h>
42 #include <sys/mutex.h>
44 #include <sys/resourcevar.h>
45 #include <sys/sysctl.h>
47 #include <machine/cpu.h>
50 * Profiling system call.
52 * The scale factor is a fixed point number with 16 bits of fraction, so that
53 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
55 #ifndef _SYS_SYSPROTO_H_
65 sys_profil(struct thread *td, struct profil_args *uap)
70 if (uap->scale > (1 << 16))
74 if (uap->scale == 0) {
81 upp = &td->td_proc->p_stats->p_prof;
83 upp->pr_off = uap->offset;
84 upp->pr_scale = uap->scale;
85 upp->pr_base = uap->samples;
86 upp->pr_size = uap->size;
95 * Scale is a fixed-point number with the binary point 16 bits
96 * into the value, and is <= 1.0. pc is at most 32 bits, so the
97 * intermediate result is at most 48 bits.
99 #define PC_TO_INDEX(pc, prof) \
100 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
101 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
104 * Collect user-level profiling statistics; called on a profiling tick,
105 * when a process is running in user-mode. This routine may be called
106 * from an interrupt context. We perform the update with an AST
107 * that will vector us to trap() with a context in which copyin and
108 * copyout will work. Trap will then call addupc_task().
110 * Note that we may (rarely) not get around to the AST soon enough, and
111 * lose profile ticks when the next tick overwrites this one, but in this
112 * case the system is overloaded and the profile is probably already
116 addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks)
122 prof = &td->td_proc->p_stats->p_prof;
123 PROC_PROFLOCK(td->td_proc);
124 if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) {
125 PROC_PROFUNLOCK(td->td_proc);
126 return; /* out of range; ignore */
129 PROC_PROFUNLOCK(td->td_proc);
130 td->td_profil_addr = pc;
131 td->td_profil_ticks = ticks;
132 td->td_pflags |= TDP_OWEUPC;
133 ast_sched(td, TDA_OWEUPC);
137 * Actually update the profiling statistics. If the update fails, we
138 * simply turn off profiling.
141 addupc_task(struct thread *td, uintfptr_t pc, u_int ticks)
143 struct proc *p = td->td_proc;
154 if (!(p->p_flag & P_PROFIL)) {
159 prof = &p->p_stats->p_prof;
161 if (pc < prof->pr_off ||
162 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
167 addr = prof->pr_base + i;
170 if (copyin(addr, &v, sizeof(v)) == 0) {
172 if (copyout(&v, addr, sizeof(v)) == 0) {
181 if (--p->p_profthreads == 0) {
182 if (p->p_flag & P_STOPPROF) {
183 wakeup(&p->p_profthreads);
184 p->p_flag &= ~P_STOPPROF;