6a70163fcc
not completely decided at config time. Just don't default to using the TSC if there are multiple active CPUs. Also, don't default to using the TSC if it is broken. SMP ifdefs are still used to disallow using perfmon since perfmon is always broken if SMP is just configured. This only helps much for SMP kernels running on 1 CPU. The overheads for using the i8254 cputime clock were a bit too high on 486/33's, and now on multi-GHz CPUs they are usually in the 99-99.9% range. Switching from the old default of an i8254 clock to the TSC works poorly because the overheads are not recalibrated. Use the same condition for declaring perfmon stuff as for using it.
342 lines
9.5 KiB
C
342 lines
9.5 KiB
C
/*-
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* Copyright (c) 1996 Bruce D. Evans.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#ifdef GUPROF
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#include "opt_i586_guprof.h"
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#include "opt_perfmon.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/gmon.h>
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#include <sys/kernel.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <machine/clock.h>
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#include <machine/perfmon.h>
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#include <machine/timerreg.h>
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#define CPUTIME_CLOCK_UNINITIALIZED 0
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#define CPUTIME_CLOCK_I8254 1
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#define CPUTIME_CLOCK_TSC 2
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#define CPUTIME_CLOCK_I586_PMC 3
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#define CPUTIME_CLOCK_I8254_SHIFT 7
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int cputime_bias = 1; /* initialize for locality of reference */
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static int cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
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#if defined(PERFMON) && defined(I586_PMC_GUPROF)
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static u_int cputime_clock_pmc_conf = I586_PMC_GUPROF;
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static int cputime_clock_pmc_init;
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static struct gmonparam saved_gmp;
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#endif
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#endif /* GUPROF */
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#ifdef __GNUCLIKE_ASM
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__asm(" \n\
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GM_STATE = 0 \n\
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GMON_PROF_OFF = 3 \n\
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\n\
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.text \n\
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.p2align 4,0x90 \n\
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.globl __mcount \n\
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.type __mcount,@function \n\
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__mcount: \n\
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# \n\
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# Check that we are profiling. Do it early for speed. \n\
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# \n\
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cmpl $GMON_PROF_OFF,_gmonparam+GM_STATE \n\
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je .mcount_exit \n\
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# \n\
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# __mcount is the same as [.]mcount except the caller \n\
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# hasn't changed the stack except to call here, so the \n\
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# caller's raddr is above our raddr. \n\
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# \n\
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movl 4(%esp),%edx \n\
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jmp .got_frompc \n\
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\n\
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.p2align 4,0x90 \n\
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.globl .mcount \n\
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.mcount: \n\
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.globl __cyg_profile_func_enter \n\
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__cyg_profile_func_enter: \n\
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cmpl $GMON_PROF_OFF,_gmonparam+GM_STATE \n\
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je .mcount_exit \n\
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# \n\
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# The caller's stack frame has already been built, so \n\
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# %ebp is the caller's frame pointer. The caller's \n\
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# raddr is in the caller's frame following the caller's \n\
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# caller's frame pointer. \n\
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# \n\
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movl 4(%ebp),%edx \n\
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.got_frompc: \n\
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# \n\
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# Our raddr is the caller's pc. \n\
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# \n\
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movl (%esp),%eax \n\
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\n\
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pushfl \n\
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pushl %eax \n\
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pushl %edx \n\
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cli \n\
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call mcount \n\
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addl $8,%esp \n\
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popfl \n\
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.mcount_exit: \n\
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ret \n\
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");
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#else /* !__GNUCLIKE_ASM */
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#error "this file needs to be ported to your compiler"
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#endif /* __GNUCLIKE_ASM */
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#ifdef GUPROF
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/*
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* [.]mexitcount saves the return register(s), loads selfpc and calls
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* mexitcount(selfpc) to do the work. Someday it should be in a machine
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* dependent file together with cputime(), __mcount and [.]mcount. cputime()
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* can't just be put in machdep.c because it has to be compiled without -pg.
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*/
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#ifdef __GNUCLIKE_ASM
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__asm(" \n\
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.text \n\
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# \n\
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# Dummy label to be seen when gprof -u hides [.]mexitcount. \n\
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# \n\
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.p2align 4,0x90 \n\
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.globl __mexitcount \n\
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.type __mexitcount,@function \n\
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__mexitcount: \n\
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nop \n\
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\n\
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GMON_PROF_HIRES = 4 \n\
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\n\
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.p2align 4,0x90 \n\
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.globl .mexitcount \n\
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.mexitcount: \n\
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.globl __cyg_profile_func_exit \n\
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__cyg_profile_func_exit: \n\
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cmpl $GMON_PROF_HIRES,_gmonparam+GM_STATE \n\
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jne .mexitcount_exit \n\
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pushl %edx \n\
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pushl %eax \n\
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movl 8(%esp),%eax \n\
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pushfl \n\
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pushl %eax \n\
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cli \n\
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call mexitcount \n\
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addl $4,%esp \n\
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popfl \n\
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popl %eax \n\
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popl %edx \n\
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.mexitcount_exit: \n\
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ret \n\
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");
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#endif /* __GNUCLIKE_ASM */
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/*
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* Return the time elapsed since the last call. The units are machine-
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* dependent.
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*/
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int
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cputime()
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{
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u_int count;
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int delta;
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#if (defined(I586_CPU) || defined(I686_CPU)) && !defined(SMP) && \
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defined(PERFMON) && defined(I586_PMC_GUPROF)
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u_quad_t event_count;
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#endif
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u_char high, low;
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static u_int prev_count;
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#if defined(I586_CPU) || defined(I686_CPU)
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if (cputime_clock == CPUTIME_CLOCK_TSC) {
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/*
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* Scale the TSC a little to make cputime()'s frequency
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* fit in an int, assuming that the TSC frequency fits
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* in a u_int. Use a fixed scale since dynamic scaling
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* would be slower and we can't really use the low bit
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* of precision.
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*/
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count = (u_int)rdtsc() & ~1u;
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delta = (int)(count - prev_count) >> 1;
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prev_count = count;
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return (delta);
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}
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#if defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
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if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
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/*
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* XXX permon_read() should be inlined so that the
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* perfmon module doesn't need to be compiled with
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* profiling disabled and so that it is fast.
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*/
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perfmon_read(0, &event_count);
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count = (u_int)event_count;
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delta = (int)(count - prev_count);
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prev_count = count;
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return (delta);
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}
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#endif /* PERFMON && I586_PMC_GUPROF && !SMP */
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#endif /* I586_CPU || I686_CPU */
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/*
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* Read the current value of the 8254 timer counter 0.
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*/
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outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
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low = inb(TIMER_CNTR0);
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high = inb(TIMER_CNTR0);
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count = ((high << 8) | low) << CPUTIME_CLOCK_I8254_SHIFT;
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/*
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* The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
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* While profiling is enabled, this routine is called at least twice
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* per timer reset (for mcounting and mexitcounting hardclock()),
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* so at most one reset has occurred since the last call, and one
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* has occurred iff the current count is larger than the previous
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* count. This allows counter underflow to be detected faster
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* than in microtime().
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*/
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delta = prev_count - count;
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prev_count = count;
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if ((int) delta <= 0)
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return (delta + (timer0_max_count << CPUTIME_CLOCK_I8254_SHIFT));
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return (delta);
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}
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static int
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sysctl_machdep_cputime_clock(SYSCTL_HANDLER_ARGS)
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{
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int clock;
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int error;
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#if defined(PERFMON) && defined(I586_PMC_GUPROF)
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int event;
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struct pmc pmc;
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#endif
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clock = cputime_clock;
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#if defined(PERFMON) && defined(I586_PMC_GUPROF)
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if (clock == CPUTIME_CLOCK_I586_PMC) {
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pmc.pmc_val = cputime_clock_pmc_conf;
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clock += pmc.pmc_event;
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}
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#endif
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error = sysctl_handle_opaque(oidp, &clock, sizeof clock, req);
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if (error == 0 && req->newptr != NULL) {
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#if defined(PERFMON) && defined(I586_PMC_GUPROF)
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if (clock >= CPUTIME_CLOCK_I586_PMC) {
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event = clock - CPUTIME_CLOCK_I586_PMC;
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if (event >= 256)
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return (EINVAL);
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pmc.pmc_num = 0;
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pmc.pmc_event = event;
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pmc.pmc_unit = 0;
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pmc.pmc_flags = PMCF_E | PMCF_OS | PMCF_USR;
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pmc.pmc_mask = 0;
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cputime_clock_pmc_conf = pmc.pmc_val;
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cputime_clock = CPUTIME_CLOCK_I586_PMC;
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} else
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#endif
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{
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if (clock < 0 || clock >= CPUTIME_CLOCK_I586_PMC)
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return (EINVAL);
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cputime_clock = clock;
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}
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}
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return (error);
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}
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SYSCTL_PROC(_machdep, OID_AUTO, cputime_clock, CTLTYPE_INT | CTLFLAG_RW,
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0, sizeof(u_int), sysctl_machdep_cputime_clock, "I", "");
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/*
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* The start and stop routines need not be here since we turn off profiling
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* before calling them. They are here for convenience.
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*/
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void
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startguprof(gp)
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struct gmonparam *gp;
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{
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if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
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cputime_clock = CPUTIME_CLOCK_I8254;
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#if defined(I586_CPU) || defined(I686_CPU)
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if (tsc_freq != 0 && !tsc_is_broken && mp_ncpus < 2)
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cputime_clock = CPUTIME_CLOCK_TSC;
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#endif
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}
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gp->profrate = timer_freq << CPUTIME_CLOCK_I8254_SHIFT;
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#if defined(I586_CPU) || defined(I686_CPU)
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if (cputime_clock == CPUTIME_CLOCK_TSC)
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gp->profrate = tsc_freq >> 1;
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#if defined(PERFMON) && defined(I586_PMC_GUPROF)
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else if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
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if (perfmon_avail() &&
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perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
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if (perfmon_start(0) != 0)
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perfmon_fini(0);
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else {
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/* XXX 1 event == 1 us. */
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gp->profrate = 1000000;
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saved_gmp = *gp;
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/* Zap overheads. They are invalid. */
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gp->cputime_overhead = 0;
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gp->mcount_overhead = 0;
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gp->mcount_post_overhead = 0;
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gp->mcount_pre_overhead = 0;
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gp->mexitcount_overhead = 0;
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gp->mexitcount_post_overhead = 0;
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gp->mexitcount_pre_overhead = 0;
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cputime_clock_pmc_init = TRUE;
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}
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}
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}
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#endif /* PERFMON && I586_PMC_GUPROF */
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#endif /* I586_CPU || I686_CPU */
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cputime_bias = 0;
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cputime();
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}
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void
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stopguprof(gp)
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struct gmonparam *gp;
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{
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#if defined(PERFMON) && defined(I586_PMC_GUPROF)
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if (cputime_clock_pmc_init) {
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*gp = saved_gmp;
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perfmon_fini(0);
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cputime_clock_pmc_init = FALSE;
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}
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#endif
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}
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#endif /* GUPROF */
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