The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/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: releng/8.0/sys/amd64/amd64/prof_machdep.c 184102 2008-10-21 00:38:00Z jkim $");
   29 
   30 #ifdef GUPROF
   31 #if 0
   32 #include "opt_i586_guprof.h"
   33 #include "opt_perfmon.h"
   34 #endif
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/bus.h>
   39 #include <sys/cpu.h>
   40 #include <sys/eventhandler.h>
   41 #include <sys/gmon.h>
   42 #include <sys/kernel.h>
   43 #include <sys/smp.h>
   44 #include <sys/sysctl.h>
   45 
   46 #include <machine/clock.h>
   47 #if 0
   48 #include <machine/perfmon.h>
   49 #endif
   50 #include <machine/timerreg.h>
   51 
   52 #define CPUTIME_CLOCK_UNINITIALIZED     0
   53 #define CPUTIME_CLOCK_I8254             1
   54 #define CPUTIME_CLOCK_TSC               2
   55 #define CPUTIME_CLOCK_I586_PMC          3
   56 #define CPUTIME_CLOCK_I8254_SHIFT       7
   57 
   58 int     cputime_bias = 1;       /* initialize for locality of reference */
   59 
   60 static int      cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
   61 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
   62 static u_int    cputime_clock_pmc_conf = I586_PMC_GUPROF;
   63 static int      cputime_clock_pmc_init;
   64 static struct gmonparam saved_gmp;
   65 #endif
   66 #if defined(I586_CPU) || defined(I686_CPU)
   67 static int      cputime_prof_active;
   68 #endif
   69 #endif /* GUPROF */
   70 
   71 #ifdef __GNUCLIKE_ASM
   72 __asm("                                                         \n\
   73 GM_STATE        =       0                                       \n\
   74 GMON_PROF_OFF   =       3                                       \n\
   75                                                                 \n\
   76         .text                                                   \n\
   77         .p2align 4,0x90                                         \n\
   78         .globl  __mcount                                        \n\
   79         .type   __mcount,@function                              \n\
   80 __mcount:                                                       \n\
   81         #                                                       \n\
   82         # Check that we are profiling.  Do it early for speed.  \n\
   83         #                                                       \n\
   84         cmpl    $GMON_PROF_OFF,_gmonparam+GM_STATE              \n\
   85         je      .mcount_exit                                    \n\
   86         #                                                       \n\
   87         # __mcount is the same as [.]mcount except the caller   \n\
   88         # hasn't changed the stack except to call here, so the  \n\
   89         # caller's raddr is above our raddr.                    \n\
   90         #                                                       \n\
   91         pushq   %rax                                            \n\
   92         pushq   %rdx                                            \n\
   93         pushq   %rcx                                            \n\
   94         pushq   %rsi                                            \n\
   95         pushq   %rdi                                            \n\
   96         pushq   %r8                                             \n\
   97         pushq   %r9                                             \n\
   98         movq    7*8+8(%rsp),%rdi                                \n\
   99         jmp     .got_frompc                                     \n\
  100                                                                 \n\
  101         .p2align 4,0x90                                         \n\
  102         .globl  .mcount                                         \n\
  103 .mcount:                                                        \n\
  104         cmpl    $GMON_PROF_OFF,_gmonparam+GM_STATE              \n\
  105         je      .mcount_exit                                    \n\
  106         #                                                       \n\
  107         # The caller's stack frame has already been built, so   \n\
  108         # %rbp is the caller's frame pointer.  The caller's     \n\
  109         # raddr is in the caller's frame following the caller's \n\
  110         # caller's frame pointer.                               \n\
  111         #                                                       \n\
  112         pushq   %rax                                            \n\
  113         pushq   %rdx                                            \n\
  114         pushq   %rcx                                            \n\
  115         pushq   %rsi                                            \n\
  116         pushq   %rdi                                            \n\
  117         pushq   %r8                                             \n\
  118         pushq   %r9                                             \n\
  119         movq    8(%rbp),%rdi                                    \n\
  120 .got_frompc:                                                    \n\
  121         #                                                       \n\
  122         # Our raddr is the caller's pc.                         \n\
  123         #                                                       \n\
  124         movq    7*8(%rsp),%rsi                                  \n\
  125                                                                 \n\
  126         pushfq                                                  \n\
  127         cli                                                     \n\
  128         call    mcount                                          \n\
  129         popfq                                                   \n\
  130         popq    %r9                                             \n\
  131         popq    %r8                                             \n\
  132         popq    %rdi                                            \n\
  133         popq    %rsi                                            \n\
  134         popq    %rcx                                            \n\
  135         popq    %rdx                                            \n\
  136         popq    %rax                                            \n\
  137 .mcount_exit:                                                   \n\
  138         ret     $0                                              \n\
  139 ");
  140 #else /* !__GNUCLIKE_ASM */
  141 #error "this file needs to be ported to your compiler"
  142 #endif /* __GNUCLIKE_ASM */
  143 
  144 #ifdef GUPROF
  145 /*
  146  * [.]mexitcount saves the return register(s), loads selfpc and calls
  147  * mexitcount(selfpc) to do the work.  Someday it should be in a machine
  148  * dependent file together with cputime(), __mcount and [.]mcount.  cputime()
  149  * can't just be put in machdep.c because it has to be compiled without -pg.
  150  */
  151 #ifdef __GNUCLIKE_ASM
  152 __asm("                                                         \n\
  153         .text                                                   \n\
  154 #                                                               \n\
  155 # Dummy label to be seen when gprof -u hides [.]mexitcount.     \n\
  156 #                                                               \n\
  157         .p2align 4,0x90                                         \n\
  158         .globl  __mexitcount                                    \n\
  159         .type   __mexitcount,@function                          \n\
  160 __mexitcount:                                                   \n\
  161         nop                                                     \n\
  162                                                                 \n\
  163 GMON_PROF_HIRES =       4                                       \n\
  164                                                                 \n\
  165         .p2align 4,0x90                                         \n\
  166         .globl  .mexitcount                                     \n\
  167 .mexitcount:                                                    \n\
  168         cmpl    $GMON_PROF_HIRES,_gmonparam+GM_STATE            \n\
  169         jne     .mexitcount_exit                                \n\
  170         pushq   %rax                                            \n\
  171         pushq   %rdx                                            \n\
  172         pushq   %rcx                                            \n\
  173         pushq   %rsi                                            \n\
  174         pushq   %rdi                                            \n\
  175         pushq   %r8                                             \n\
  176         pushq   %r9                                             \n\
  177         movq    7*8(%rsp),%rdi                                  \n\
  178         pushfq                                                  \n\
  179         cli                                                     \n\
  180         call    mexitcount                                      \n\
  181         popfq                                                   \n\
  182         popq    %r9                                             \n\
  183         popq    %r8                                             \n\
  184         popq    %rdi                                            \n\
  185         popq    %rsi                                            \n\
  186         popq    %rcx                                            \n\
  187         popq    %rdx                                            \n\
  188         popq    %rax                                            \n\
  189 .mexitcount_exit:                                               \n\
  190         ret     $0                                              \n\
  191 ");
  192 #endif /* __GNUCLIKE_ASM */
  193 
  194 /*
  195  * Return the time elapsed since the last call.  The units are machine-
  196  * dependent.
  197  */
  198 int
  199 cputime()
  200 {
  201         u_int count;
  202         int delta;
  203 #if (defined(I586_CPU) || defined(I686_CPU)) && !defined(SMP) && \
  204     defined(PERFMON) && defined(I586_PMC_GUPROF)
  205         u_quad_t event_count;
  206 #endif
  207         u_char high, low;
  208         static u_int prev_count;
  209 
  210 #if defined(I586_CPU) || defined(I686_CPU)
  211         if (cputime_clock == CPUTIME_CLOCK_TSC) {
  212                 /*
  213                  * Scale the TSC a little to make cputime()'s frequency
  214                  * fit in an int, assuming that the TSC frequency fits
  215                  * in a u_int.  Use a fixed scale since dynamic scaling
  216                  * would be slower and we can't really use the low bit
  217                  * of precision.
  218                  */
  219                 count = (u_int)rdtsc() & ~1u;
  220                 delta = (int)(count - prev_count) >> 1;
  221                 prev_count = count;
  222                 return (delta);
  223         }
  224 #if defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
  225         if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
  226                 /*
  227                  * XXX permon_read() should be inlined so that the
  228                  * perfmon module doesn't need to be compiled with
  229                  * profiling disabled and so that it is fast.
  230                  */
  231                 perfmon_read(0, &event_count);
  232 
  233                 count = (u_int)event_count;
  234                 delta = (int)(count - prev_count);
  235                 prev_count = count;
  236                 return (delta);
  237         }
  238 #endif /* PERFMON && I586_PMC_GUPROF && !SMP */
  239 #endif /* I586_CPU || I686_CPU */
  240 
  241         /*
  242          * Read the current value of the 8254 timer counter 0.
  243          */
  244         outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
  245         low = inb(TIMER_CNTR0);
  246         high = inb(TIMER_CNTR0);
  247         count = ((high << 8) | low) << CPUTIME_CLOCK_I8254_SHIFT;
  248 
  249         /*
  250          * The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
  251          * While profiling is enabled, this routine is called at least twice
  252          * per timer reset (for mcounting and mexitcounting hardclock()),
  253          * so at most one reset has occurred since the last call, and one
  254          * has occurred iff the current count is larger than the previous
  255          * count.  This allows counter underflow to be detected faster
  256          * than in microtime().
  257          */
  258         delta = prev_count - count;
  259         prev_count = count;
  260         if ((int) delta <= 0)
  261                 return (delta + (i8254_max_count << CPUTIME_CLOCK_I8254_SHIFT));
  262         return (delta);
  263 }
  264 
  265 static int
  266 sysctl_machdep_cputime_clock(SYSCTL_HANDLER_ARGS)
  267 {
  268         int clock;
  269         int error;
  270 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  271         int event;
  272         struct pmc pmc;
  273 #endif
  274 
  275         clock = cputime_clock;
  276 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  277         if (clock == CPUTIME_CLOCK_I586_PMC) {
  278                 pmc.pmc_val = cputime_clock_pmc_conf;
  279                 clock += pmc.pmc_event;
  280         }
  281 #endif
  282         error = sysctl_handle_opaque(oidp, &clock, sizeof clock, req);
  283         if (error == 0 && req->newptr != NULL) {
  284 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  285                 if (clock >= CPUTIME_CLOCK_I586_PMC) {
  286                         event = clock - CPUTIME_CLOCK_I586_PMC;
  287                         if (event >= 256)
  288                                 return (EINVAL);
  289                         pmc.pmc_num = 0;
  290                         pmc.pmc_event = event;
  291                         pmc.pmc_unit = 0;
  292                         pmc.pmc_flags = PMCF_E | PMCF_OS | PMCF_USR;
  293                         pmc.pmc_mask = 0;
  294                         cputime_clock_pmc_conf = pmc.pmc_val;
  295                         cputime_clock = CPUTIME_CLOCK_I586_PMC;
  296                 } else
  297 #endif
  298                 {
  299                         if (clock < 0 || clock >= CPUTIME_CLOCK_I586_PMC)
  300                                 return (EINVAL);
  301                         cputime_clock = clock;
  302                 }
  303         }
  304         return (error);
  305 }
  306 
  307 SYSCTL_PROC(_machdep, OID_AUTO, cputime_clock, CTLTYPE_INT | CTLFLAG_RW,
  308             0, sizeof(u_int), sysctl_machdep_cputime_clock, "I", "");
  309 
  310 /*
  311  * The start and stop routines need not be here since we turn off profiling
  312  * before calling them.  They are here for convenience.
  313  */
  314 
  315 void
  316 startguprof(gp)
  317         struct gmonparam *gp;
  318 {
  319         if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
  320                 cputime_clock = CPUTIME_CLOCK_I8254;
  321 #if defined(I586_CPU) || defined(I686_CPU)
  322                 if (tsc_freq != 0 && !tsc_is_broken && mp_ncpus == 1)
  323                         cputime_clock = CPUTIME_CLOCK_TSC;
  324 #endif
  325         }
  326         gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
  327 #if defined(I586_CPU) || defined(I686_CPU)
  328         if (cputime_clock == CPUTIME_CLOCK_TSC) {
  329                 gp->profrate = tsc_freq >> 1;
  330                 cputime_prof_active = 1;
  331         }
  332 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  333         else if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
  334                 if (perfmon_avail() &&
  335                     perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
  336                         if (perfmon_start(0) != 0)
  337                                 perfmon_fini(0);
  338                         else {
  339                                 /* XXX 1 event == 1 us. */
  340                                 gp->profrate = 1000000;
  341 
  342                                 saved_gmp = *gp;
  343 
  344                                 /* Zap overheads.  They are invalid. */
  345                                 gp->cputime_overhead = 0;
  346                                 gp->mcount_overhead = 0;
  347                                 gp->mcount_post_overhead = 0;
  348                                 gp->mcount_pre_overhead = 0;
  349                                 gp->mexitcount_overhead = 0;
  350                                 gp->mexitcount_post_overhead = 0;
  351                                 gp->mexitcount_pre_overhead = 0;
  352 
  353                                 cputime_clock_pmc_init = TRUE;
  354                         }
  355                 }
  356         }
  357 #endif /* PERFMON && I586_PMC_GUPROF */
  358 #endif /* I586_CPU || I686_CPU */
  359         cputime_bias = 0;
  360         cputime();
  361 }
  362 
  363 void
  364 stopguprof(gp)
  365         struct gmonparam *gp;
  366 {
  367 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  368         if (cputime_clock_pmc_init) {
  369                 *gp = saved_gmp;
  370                 perfmon_fini(0);
  371                 cputime_clock_pmc_init = FALSE;
  372         }
  373 #endif
  374 #if defined(I586_CPU) || defined(I686_CPU)
  375         if (cputime_clock == CPUTIME_CLOCK_TSC)
  376                 cputime_prof_active = 0;
  377 #endif
  378 }
  379 
  380 #if defined(I586_CPU) || defined(I686_CPU)
  381 /* If the cpu frequency changed while profiling, report a warning. */
  382 static void
  383 tsc_freq_changed(void *arg, const struct cf_level *level, int status)
  384 {
  385 
  386         /*
  387          * If there was an error during the transition or
  388          * TSC is P-state invariant, don't do anything.
  389          */
  390         if (status != 0 || tsc_is_invariant)
  391                 return;
  392         if (cputime_prof_active && cputime_clock == CPUTIME_CLOCK_TSC)
  393                 printf("warning: cpu freq changed while profiling active\n");
  394 }
  395 
  396 EVENTHANDLER_DEFINE(cpufreq_post_change, tsc_freq_changed, NULL,
  397     EVENTHANDLER_PRI_ANY);
  398 #endif /* I586_CPU || I686_CPU */
  399 
  400 #endif /* GUPROF */

Cache object: 68dca1465314c48242947189d873a7b3


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