The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/i386/isa/prof_machdep.c

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    1 /*-
    2  * Copyright (c) 1996 Bruce D. Evans.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: stable/11/sys/i386/isa/prof_machdep.c 331722 2018-03-29 02:50:57Z eadler $");
   29 
   30 #ifdef GUPROF
   31 #include "opt_i586_guprof.h"
   32 #include "opt_perfmon.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/bus.h>
   37 #include <sys/cpu.h>
   38 #include <sys/eventhandler.h>
   39 #include <sys/gmon.h>
   40 #include <sys/kernel.h>
   41 #include <sys/smp.h>
   42 #include <sys/sysctl.h>
   43 
   44 #include <machine/clock.h>
   45 #include <machine/perfmon.h>
   46 #include <machine/timerreg.h>
   47 
   48 #define CPUTIME_CLOCK_UNINITIALIZED     0
   49 #define CPUTIME_CLOCK_I8254             1
   50 #define CPUTIME_CLOCK_TSC               2
   51 #define CPUTIME_CLOCK_I586_PMC          3
   52 #define CPUTIME_CLOCK_I8254_SHIFT       7
   53 
   54 int     cputime_bias = 1;       /* initialize for locality of reference */
   55 
   56 static int      cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
   57 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
   58 static u_int    cputime_clock_pmc_conf = I586_PMC_GUPROF;
   59 static int      cputime_clock_pmc_init;
   60 static struct gmonparam saved_gmp;
   61 #endif
   62 #if defined(I586_CPU) || defined(I686_CPU)
   63 static int      cputime_prof_active;
   64 #endif
   65 #endif /* GUPROF */
   66 
   67 #ifdef __GNUCLIKE_ASM
   68 __asm("                                                         \n\
   69 GM_STATE        =       0                                       \n\
   70 GMON_PROF_OFF   =       3                                       \n\
   71                                                                 \n\
   72         .text                                                   \n\
   73         .p2align 4,0x90                                         \n\
   74         .globl  __mcount                                        \n\
   75         .type   __mcount,@function                              \n\
   76 __mcount:                                                       \n\
   77         #                                                       \n\
   78         # Check that we are profiling.  Do it early for speed.  \n\
   79         #                                                       \n\
   80         cmpl    $GMON_PROF_OFF,_gmonparam+GM_STATE              \n\
   81         je      .mcount_exit                                    \n\
   82         #                                                       \n\
   83         # __mcount is the same as [.]mcount except the caller   \n\
   84         # hasn't changed the stack except to call here, so the  \n\
   85         # caller's raddr is above our raddr.                    \n\
   86         #                                                       \n\
   87         movl    4(%esp),%edx                                    \n\
   88         jmp     .got_frompc                                     \n\
   89                                                                 \n\
   90         .p2align 4,0x90                                         \n\
   91         .globl  .mcount                                         \n\
   92 .mcount:                                                        \n\
   93         cmpl    $GMON_PROF_OFF,_gmonparam+GM_STATE              \n\
   94         je      .mcount_exit                                    \n\
   95         #                                                       \n\
   96         # The caller's stack frame has already been built, so   \n\
   97         # %ebp is the caller's frame pointer.  The caller's     \n\
   98         # raddr is in the caller's frame following the caller's \n\
   99         # caller's frame pointer.                               \n\
  100         #                                                       \n\
  101         movl    4(%ebp),%edx                                    \n\
  102 .got_frompc:                                                    \n\
  103         #                                                       \n\
  104         # Our raddr is the caller's pc.                         \n\
  105         #                                                       \n\
  106         movl    (%esp),%eax                                     \n\
  107                                                                 \n\
  108         pushfl                                                  \n\
  109         pushl   %eax                                            \n\
  110         pushl   %edx                                            \n\
  111         cli                                                     \n\
  112         call    mcount                                          \n\
  113         addl    $8,%esp                                         \n\
  114         popfl                                                   \n\
  115 .mcount_exit:                                                   \n\
  116         ret     $0                                              \n\
  117 ");
  118 #else /* !__GNUCLIKE_ASM */
  119 #error "this file needs to be ported to your compiler"
  120 #endif /* __GNUCLIKE_ASM */
  121 
  122 #ifdef GUPROF
  123 /*
  124  * [.]mexitcount saves the return register(s), loads selfpc and calls
  125  * mexitcount(selfpc) to do the work.  Someday it should be in a machine
  126  * dependent file together with cputime(), __mcount and [.]mcount.  cputime()
  127  * can't just be put in machdep.c because it has to be compiled without -pg.
  128  */
  129 #ifdef __GNUCLIKE_ASM
  130 __asm("                                                         \n\
  131         .text                                                   \n\
  132 #                                                               \n\
  133 # Dummy label to be seen when gprof -u hides [.]mexitcount.     \n\
  134 #                                                               \n\
  135         .p2align 4,0x90                                         \n\
  136         .globl  __mexitcount                                    \n\
  137         .type   __mexitcount,@function                          \n\
  138 __mexitcount:                                                   \n\
  139         nop                                                     \n\
  140                                                                 \n\
  141 GMON_PROF_HIRES =       4                                       \n\
  142                                                                 \n\
  143         .p2align 4,0x90                                         \n\
  144         .globl  .mexitcount                                     \n\
  145 .mexitcount:                                                    \n\
  146         cmpl    $GMON_PROF_HIRES,_gmonparam+GM_STATE            \n\
  147         jne     .mexitcount_exit                                \n\
  148         pushl   %edx                                            \n\
  149         pushl   %eax                                            \n\
  150         movl    8(%esp),%eax                                    \n\
  151         pushfl                                                  \n\
  152         pushl   %eax                                            \n\
  153         cli                                                     \n\
  154         call    mexitcount                                      \n\
  155         addl    $4,%esp                                         \n\
  156         popfl                                                   \n\
  157         popl    %eax                                            \n\
  158         popl    %edx                                            \n\
  159 .mexitcount_exit:                                               \n\
  160         ret     $0                                              \n\
  161 ");
  162 #endif /* __GNUCLIKE_ASM */
  163 
  164 /*
  165  * Return the time elapsed since the last call.  The units are machine-
  166  * dependent.
  167  */
  168 int
  169 cputime()
  170 {
  171         u_int count;
  172         int delta;
  173 #if (defined(I586_CPU) || defined(I686_CPU)) && \
  174     defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
  175         u_quad_t event_count;
  176 #endif
  177         u_char high, low;
  178         static u_int prev_count;
  179 
  180 #if defined(I586_CPU) || defined(I686_CPU)
  181         if (cputime_clock == CPUTIME_CLOCK_TSC) {
  182                 /*
  183                  * Scale the TSC a little to make cputime()'s frequency
  184                  * fit in an int, assuming that the TSC frequency fits
  185                  * in a u_int.  Use a fixed scale since dynamic scaling
  186                  * would be slower and we can't really use the low bit
  187                  * of precision.
  188                  */
  189                 count = (u_int)rdtsc() & ~1u;
  190                 delta = (int)(count - prev_count) >> 1;
  191                 prev_count = count;
  192                 return (delta);
  193         }
  194 #if defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
  195         if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
  196                 /*
  197                  * XXX permon_read() should be inlined so that the
  198                  * perfmon module doesn't need to be compiled with
  199                  * profiling disabled and so that it is fast.
  200                  */
  201                 perfmon_read(0, &event_count);
  202 
  203                 count = (u_int)event_count;
  204                 delta = (int)(count - prev_count);
  205                 prev_count = count;
  206                 return (delta);
  207         }
  208 #endif /* PERFMON && I586_PMC_GUPROF && !SMP */
  209 #endif /* I586_CPU || I686_CPU */
  210 
  211         /*
  212          * Read the current value of the 8254 timer counter 0.
  213          */
  214         outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
  215         low = inb(TIMER_CNTR0);
  216         high = inb(TIMER_CNTR0);
  217         count = ((high << 8) | low) << CPUTIME_CLOCK_I8254_SHIFT;
  218 
  219         /*
  220          * The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
  221          * While profiling is enabled, this routine is called at least twice
  222          * per timer reset (for mcounting and mexitcounting hardclock()),
  223          * so at most one reset has occurred since the last call, and one
  224          * has occurred iff the current count is larger than the previous
  225          * count.  This allows counter underflow to be detected faster
  226          * than in microtime().
  227          */
  228         delta = prev_count - count;
  229         prev_count = count;
  230         if ((int) delta <= 0)
  231                 return (delta + (i8254_max_count << CPUTIME_CLOCK_I8254_SHIFT));
  232         return (delta);
  233 }
  234 
  235 static int
  236 sysctl_machdep_cputime_clock(SYSCTL_HANDLER_ARGS)
  237 {
  238         int clock;
  239         int error;
  240 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  241         int event;
  242         struct pmc pmc;
  243 #endif
  244 
  245         clock = cputime_clock;
  246 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  247         if (clock == CPUTIME_CLOCK_I586_PMC) {
  248                 pmc.pmc_val = cputime_clock_pmc_conf;
  249                 clock += pmc.pmc_event;
  250         }
  251 #endif
  252         error = sysctl_handle_opaque(oidp, &clock, sizeof clock, req);
  253         if (error == 0 && req->newptr != NULL) {
  254 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  255                 if (clock >= CPUTIME_CLOCK_I586_PMC) {
  256                         event = clock - CPUTIME_CLOCK_I586_PMC;
  257                         if (event >= 256)
  258                                 return (EINVAL);
  259                         pmc.pmc_num = 0;
  260                         pmc.pmc_event = event;
  261                         pmc.pmc_unit = 0;
  262                         pmc.pmc_flags = PMCF_E | PMCF_OS | PMCF_USR;
  263                         pmc.pmc_mask = 0;
  264                         cputime_clock_pmc_conf = pmc.pmc_val;
  265                         cputime_clock = CPUTIME_CLOCK_I586_PMC;
  266                 } else
  267 #endif
  268                 {
  269                         if (clock < 0 || clock >= CPUTIME_CLOCK_I586_PMC)
  270                                 return (EINVAL);
  271                         cputime_clock = clock;
  272                 }
  273         }
  274         return (error);
  275 }
  276 
  277 SYSCTL_PROC(_machdep, OID_AUTO, cputime_clock, CTLTYPE_INT | CTLFLAG_RW,
  278             0, sizeof(u_int), sysctl_machdep_cputime_clock, "I", "");
  279 
  280 /*
  281  * The start and stop routines need not be here since we turn off profiling
  282  * before calling them.  They are here for convenience.
  283  */
  284 
  285 void
  286 startguprof(gp)
  287         struct gmonparam *gp;
  288 {
  289 #if defined(I586_CPU) || defined(I686_CPU)
  290         uint64_t freq;
  291 
  292         freq = atomic_load_acq_64(&tsc_freq);
  293         if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
  294                 if (freq != 0 && mp_ncpus == 1)
  295                         cputime_clock = CPUTIME_CLOCK_TSC;
  296                 else
  297                         cputime_clock = CPUTIME_CLOCK_I8254;
  298         }
  299         if (cputime_clock == CPUTIME_CLOCK_TSC) {
  300                 gp->profrate = freq >> 1;
  301                 cputime_prof_active = 1;
  302         } else
  303                 gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
  304 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  305         if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
  306                 if (perfmon_avail() &&
  307                     perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
  308                         if (perfmon_start(0) != 0)
  309                                 perfmon_fini(0);
  310                         else {
  311                                 /* XXX 1 event == 1 us. */
  312                                 gp->profrate = 1000000;
  313 
  314                                 saved_gmp = *gp;
  315 
  316                                 /* Zap overheads.  They are invalid. */
  317                                 gp->cputime_overhead = 0;
  318                                 gp->mcount_overhead = 0;
  319                                 gp->mcount_post_overhead = 0;
  320                                 gp->mcount_pre_overhead = 0;
  321                                 gp->mexitcount_overhead = 0;
  322                                 gp->mexitcount_post_overhead = 0;
  323                                 gp->mexitcount_pre_overhead = 0;
  324 
  325                                 cputime_clock_pmc_init = TRUE;
  326                         }
  327                 }
  328         }
  329 #endif /* PERFMON && I586_PMC_GUPROF */
  330 #else /* !(I586_CPU || I686_CPU) */
  331         if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED)
  332                 cputime_clock = CPUTIME_CLOCK_I8254;
  333         gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
  334 #endif /* I586_CPU || I686_CPU */
  335         cputime_bias = 0;
  336         cputime();
  337 }
  338 
  339 void
  340 stopguprof(gp)
  341         struct gmonparam *gp;
  342 {
  343 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  344         if (cputime_clock_pmc_init) {
  345                 *gp = saved_gmp;
  346                 perfmon_fini(0);
  347                 cputime_clock_pmc_init = FALSE;
  348         }
  349 #endif
  350 #if defined(I586_CPU) || defined(I686_CPU)
  351         if (cputime_clock == CPUTIME_CLOCK_TSC)
  352                 cputime_prof_active = 0;
  353 #endif
  354 }
  355 
  356 #if defined(I586_CPU) || defined(I686_CPU)
  357 /* If the cpu frequency changed while profiling, report a warning. */
  358 static void
  359 tsc_freq_changed(void *arg, const struct cf_level *level, int status)
  360 {
  361 
  362         /*
  363          * If there was an error during the transition or
  364          * TSC is P-state invariant, don't do anything.
  365          */
  366         if (status != 0 || tsc_is_invariant)
  367                 return;
  368         if (cputime_prof_active && cputime_clock == CPUTIME_CLOCK_TSC)
  369                 printf("warning: cpu freq changed while profiling active\n");
  370 }
  371 
  372 EVENTHANDLER_DEFINE(cpufreq_post_change, tsc_freq_changed, NULL,
  373     EVENTHANDLER_PRI_ANY);
  374 #endif /* I586_CPU || I686_CPU */
  375 
  376 #endif /* GUPROF */

Cache object: 347121a7fc330221eddea5c38ea5b9cd


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