plugins/vddk/stats.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdint.h>
  38 #include <inttypes.h>
  39
  40 #include <pthread.h>
  41
  42 #define NBDKIT_API_VERSION 2
  43 #include <nbdkit-plugin.h>
  44
  45 #include "vector.h"
  46
  47 #include "vddk.h"
  48
  49 /* Debug flags. */
  50 NBDKIT_DLL_PUBLIC int vddk_debug_stats;
  51
  52 pthread_mutex_t stats_lock = PTHREAD_MUTEX_INITIALIZER;
  53
  54 /* For each VDDK API define a variable to store the time taken (used
  55  * to implement -D vddk.stats=1).
  56  */
  57 #define STUB(fn, ret, args) struct vddk_stat stats_##fn = { .name = #fn }
  58 #define OPTIONAL_STUB(fn, ret, args) STUB (fn, ret, args)
  59 #include "vddk-stubs.h"
  60 #undef STUB
  61 #undef OPTIONAL_STUB
  62
  63 DEFINE_VECTOR_TYPE (statlist, struct vddk_stat);
  64
  65 static int
  66 stat_compare (const void *vp1, const void *vp2)
  67 {
  68   const struct vddk_stat *st1 = vp1;
  69   const struct vddk_stat *st2 = vp2;
  70
  71   /* Note: sorts in reverse order of time spent in each API call. */
  72   if (st1->usecs < st2->usecs) return 1;
  73   else if (st1->usecs > st2->usecs) return -1;
  74   else return 0;
  75 }
  76
  77 static const char *
  78 api_name_without_prefix (const char *name)
  79 {
  80   return strncmp (name, "VixDiskLib_", 11) == 0 ? name + 11 : name;
  81 }
  82
  83 void
  84 display_stats (void)
  85 {
  86   statlist stats = empty_vector;
  87   size_t i;
  88
  89   if (!vddk_debug_stats) return;
  90
  91 #define STUB(fn, ret, args) statlist_append (&stats, stats_##fn)
  92 #define OPTIONAL_STUB(fn, ret, args) STUB (fn, ret, args)
  93 #include "vddk-stubs.h"
  94 #undef STUB
  95 #undef OPTIONAL_STUB
  96
  97   qsort (stats.ptr, stats.len, sizeof stats.ptr[0], stat_compare);
  98
  99   nbdkit_debug ("VDDK function stats (-D vddk.stats=1):");
 100   nbdkit_debug ("%-24s  %15s %5s %15s",
 101                 "VixDiskLib_...", "µs", "calls", "bytes");
 102   for (i = 0; i < stats.len; ++i) {
 103     if (stats.ptr[i].usecs) {
 104       if (stats.ptr[i].bytes > 0)
 105         nbdkit_debug ("  %-22s %15" PRIi64 " %5" PRIu64 " %15" PRIu64,
 106                       api_name_without_prefix (stats.ptr[i].name),
 107                       stats.ptr[i].usecs,
 108                       stats.ptr[i].calls,
 109                       stats.ptr[i].bytes);
 110       else
 111         nbdkit_debug ("  %-22s %15" PRIi64 " %5" PRIu64,
 112                       api_name_without_prefix (stats.ptr[i].name),
 113                       stats.ptr[i].usecs,
 114                       stats.ptr[i].calls);
 115     }
 116   }
 117   statlist_reset (&stats);
 118 }