tweaking MemSet() performance - 7.4.5

HI,

I'm using 7.4.5 on Mac OS X (G5) and was profiling it to see why it is 
SO SLOW at committing  inserts and deletes into a large database. One 
of the many slowdowns was from MemSet. I found an old (2002) thread 
about this and retried the tests  (see below). The main point is that 
the system memset crushes pg's!! Is it possible to add a define to call 
the system memset at build time! This probably isn't the case on other 
systems.

I wanted to know the size of FunctionCallInfoData (in execQual.c) 
because the profiler said that if it was over 128 then use the system 
call.

Here are my results:

pgMemSet
* 64
0.410u 0.000s 0:00.42 97.6%     0+0k 0+0io 0pf+0w
* 128
0.600u 0.000s 0:00.61 98.3%     0+0k 0+0io 0pf+0w
* 176 Size of fcinfo is 176, used in execQual.c which was being very 
slow here!
0.790u 0.000s 0:00.79 100.0%    0+0k 0+0io 0pf+0w
* 256
1.040u 0.000s 0:01.08 96.2%     0+0k 0+0io 0pf+0w
* 512
2.030u 0.000s 0:02.04 99.5%     0+0k 0+0io 0pf+0w
* 1024
3.950u 0.010s 0:03.94 100.5%    0+0k 0+0io 0pf+0w
* 2048
7.710u 0.000s 0:07.75 99.4%     0+0k 0+0io 0pf+0w
* 4096
15.390u 0.000s 0:15.37 100.1%   0+0k 0+0io 0pf+0w

system memset
* 64
0.260u 0.000s 0:00.25 104.0%    0+0k 0+0io 0pf+0w
* 128
0.310u 0.000s 0:00.31 100.0%    0+0k 0+0io 0pf+0w
* 176 Size of fcinfo is 176
0.300u 0.010s 0:00.30 103.3%    0+0k 0+0io 0pf+0w
* 256
0.310u 0.000s 0:00.30 103.3%    0+0k 0+0io 0pf+0w
* 512
0.350u 0.000s 0:00.33 106.0%    0+0k 0+0io 0pf+0w
* 1024
0.590u 0.010s 0:00.63 95.2%     0+0k 0+0io 0pf+0w
* 2048
0.780u 0.000s 0:00.77 101.2%    0+0k 0+0io 0pf+0w
* 4096
1.320u 0.000s 0:01.33 99.2%     0+0k 0+0io 0pf+0w

 #include <string.h> #include "postgres.h" #include "fmgr.h"
 #undef MEMSET_LOOP_LIMIT #define MEMSET_LOOP_LIMIT  1000000
 int main(int argc, char **argv) {  int  len = atoi(argv[1]);  char  buffer[len];  long long i;
    FunctionCallInfoData fcinfo;    printf("Size of fcinfo is %d\n", sizeof(fcinfo));
  for (i = 0; i < 9900000; i++)   MemSet(buffer, 0, len);   //memset(buffer, 0, len);  return 0; }