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     case 15: to[ 14] = from[ 14];
  26     case 14: to[ 13] = from[ 13];
  27     case 13: to[ 12] = from[ 12];
  28     case 12: to[ 11] = from[ 11];
  29     case 11: to[ 10] = from[ 10];
  30     case 10: to[  9] = from[  9];
  31     case  9: to[  8] = from[  8];
  32     case  8: to[  7] = from[  7];
  33     case  7: to[  6] = from[  6];
  34     case  6: to[  5] = from[  5];
  35     case  5: to[  4] = from[  4];
  36     case  4: to[  3] = from[  3];
  37     case  3: to[  2] = from[  2];
  38     case  2: to[  1] = from[  1];
  39     case  1: to[  0] = from[  0];
  40     case  0: return dest;
  41     default: return ACE_OS::memcpy (dest, src, n);
  42   }
  43 }
  44
  45 void
  46 testit (int type)
  47 {
  48   char buffer[16];
  49   size_t size = 16;
  50
  51   switch (type)
  52     {
  53     case 0: smemcpy ((void*)buffer, (void*)" THIS IS A TEST", size); break;
  54     case 1:  ACE_OS::memcpy ((void*)buffer, (void*)" THIS IS A TEST", size); break;
  55     }
  56
  57 }
  58
  59 namespace { enum { ITERATIONS = 100000000 }; }
  60
  61 int
  62 run_main (int, ACE_TCHAR *[])
  63 {
  64   ACE_START_TEST (ACE_TEXT ("Memcpy_Test"));
  65
  66   //ACE_Time_Value start, now;
  67   struct timeval start, now;
  68
  69   for (int i = ITERATIONS; i > 0; --i)
  70     testit (0);
  71
  72   start = ACE_High_Res_Timer::gettimeofday_hr ();
  73   for (int j = ITERATIONS; j > 0; --j)
  74     testit (0);
  75
  76   now = ACE_High_Res_Timer::gettimeofday_hr ();
  77
  78   double fast = 1000000  *(now.tv_sec - start.tv_sec) +
  79     now.tv_usec - start.tv_usec;
  80   ACE_DEBUG ((LM_DEBUG,
  81                ACE_TEXT ("%f uSec per iteration for fast version.\n"),
  82                fast / ITERATIONS));
  83
  84   start = ACE_High_Res_Timer::gettimeofday_hr ();
  85   for (int k = ITERATIONS; k > 0; --k)
  86     testit (1);
  87
  88   now = ACE_High_Res_Timer::gettimeofday_hr ();
  89
  90   double slow = 1000000 * (now.tv_sec-start.tv_sec) + now.tv_usec - start.tv_usec;
  91   ACE_DEBUG ((LM_DEBUG,
  92                ACE_TEXT ("%f uSec per iteration for slow version.\n"),
  93                slow / ITERATIONS));
  94
  95   ACE_END_TEST;
  96
  97   return 0;
  98 }