ACE/tests/Memcpy_Test.cpp

   1 //=============================================================================
   2 /**
   3  *  @file    Memcpy_Test.cpp
   4  *
   5  *  @author Mike Marinez <mmartinez@oci.com>
   6  *
   7  * This test compares the performance of ACE_OS::memcpy with
   8  * that of smemcpy which unrolls the memcpy loop upto size = 16.
   9  */
  10 //=============================================================================
  11
  12 #include "ace/OS_NS_string.h"
  13 #include "ace/High_Res_Timer.h"
  14
  15 #include "test_config.h"
  16
  17 void *
  18 smemcpy (void *dest, const void *src, const size_t n)
  19 {
  20   unsigned char *to = static_cast<unsigned char*> (dest);
  21   const unsigned char *from = static_cast<const unsigned char*> (src);
  22   // Unroll the loop...
  23   switch (n) {
  24     case 16: to[ 15] = from[ 15];
  25     ACE_FALLTHROUGH;
  26     case 15: to[ 14] = from[ 14];
  27     ACE_FALLTHROUGH;
  28     case 14: to[ 13] = from[ 13];
  29     ACE_FALLTHROUGH;
  30     case 13: to[ 12] = from[ 12];
  31     ACE_FALLTHROUGH;
  32     case 12: to[ 11] = from[ 11];
  33     ACE_FALLTHROUGH;
  34     case 11: to[ 10] = from[ 10];
  35     ACE_FALLTHROUGH;
  36     case 10: to[  9] = from[  9];
  37     ACE_FALLTHROUGH;
  38     case  9: to[  8] = from[  8];
  39     ACE_FALLTHROUGH;
  40     case  8: to[  7] = from[  7];
  41     ACE_FALLTHROUGH;
  42     case  7: to[  6] = from[  6];
  43     ACE_FALLTHROUGH;
  44     case  6: to[  5] = from[  5];
  45     ACE_FALLTHROUGH;
  46     case  5: to[  4] = from[  4];
  47     ACE_FALLTHROUGH;
  48     case  4: to[  3] = from[  3];
  49     ACE_FALLTHROUGH;
  50     case  3: to[  2] = from[  2];
  51     ACE_FALLTHROUGH;
  52     case  2: to[  1] = from[  1];
  53     ACE_FALLTHROUGH;
  54     case  1: to[  0] = from[  0];
  55     ACE_FALLTHROUGH;
  56     case  0: return dest;
  57     default: return ACE_OS::memcpy (dest, src, n);
  58   }
  59 }
  60
  61 void
  62 testit (int type)
  63 {
  64   char buffer[16];
  65   size_t const size = 16;
  66
  67   switch (type)
  68     {
  69     case 0: smemcpy ((void*)buffer, (void*)" THIS IS A TEST", size); break;
  70     case 1:  ACE_OS::memcpy ((void*)buffer, (void*)" THIS IS A TEST", size); break;
  71     }
  72
  73 }
  74
  75 namespace { enum { ITERATIONS = 100000000 }; }
  76
  77 int
  78 run_main (int, ACE_TCHAR *[])
  79 {
  80   ACE_START_TEST (ACE_TEXT ("Memcpy_Test"));
  81
  82   //ACE_Time_Value start, now;
  83   struct timeval start, now;
  84
  85   for (int i = ITERATIONS; i > 0; --i)
  86     testit (0);
  87
  88   start = ACE_High_Res_Timer::gettimeofday_hr ();
  89   for (int j = ITERATIONS; j > 0; --j)
  90     testit (0);
  91
  92   now = ACE_High_Res_Timer::gettimeofday_hr ();
  93
  94   double fast = 1000000  *(now.tv_sec - start.tv_sec) +
  95     now.tv_usec - start.tv_usec;
  96   ACE_DEBUG ((LM_DEBUG,
  97                ACE_TEXT ("%f uSec per iteration for fast version.\n"),
  98                fast / ITERATIONS));
  99
 100   start = ACE_High_Res_Timer::gettimeofday_hr ();
 101   for (int k = ITERATIONS; k > 0; --k)
 102     testit (1);
 103
 104   now = ACE_High_Res_Timer::gettimeofday_hr ();
 105
 106   double slow = 1000000 * (now.tv_sec-start.tv_sec) + now.tv_usec - start.tv_usec;
 107   ACE_DEBUG ((LM_DEBUG,
 108                ACE_TEXT ("%f uSec per iteration for slow version.\n"),
 109                slow / ITERATIONS));
 110
 111   ACE_END_TEST;
 112
 113   return 0;
 114 }