Write-Ahead log simulated benchmark

walbench.c

#include "stdio.h"
#include "stdlib.h"


void initBuffer(char *buffer){
  if (buffer==NULL) exit (1);
  for (int n=0; n<16000; n++){
    buffer[n]=rand()%26+'a';
  }
}

int main(){

  char *buffer;
  int count = 0;
  int previous = 0;
  int bufStart = 0;
  FILE *wFile;
  int writeSize = 0; // size, in bytes, of each entry
  long fileSize = 500000000; // total file size
  long total = 0; // total bytes written (~fileSize)
  int flushSize = 32000; // number bytes written before we force flush
  
  wFile = fopen("myfile.log","w");
  buffer = (char*) malloc (16000);
  initBuffer(buffer);
  
  while (total < fileSize){
    writeSize = 1500 + rand() % 5500;
    bufStart = rand() % 8000;
    size_t written = fwrite(buffer+bufStart, sizeof(char), writeSize, wFile);
    total += written;
    count++;
    if((total - previous) > flushSize){
      fwrite("\n", sizeof(char), 1, wFile);
      fflush(wFile);
      previous = total;
    }
  }
  printf("Total number of entries forced to disk: %d\n", count);
  fclose (wFile);
  free(buffer);
  return 0;
}

With Anti-Virus:

bvan@dhcp-visitor-220-197:scratch$ time ./a.out
Total number of entries forced to disk: 2353177

real 0m12.049s
user 0m1.287s
sys 0m10.714s
bvan@dhcp-visitor-220-197:scratch$ time ./a.out
Total number of entries forced to disk: 2353177

real 0m12.494s
user 0m1.282s
sys 0m11.104s
bvan@dhcp-visitor-220-197:scratch$ time ./a.out
Total number of entries forced to disk: 2353177

real 0m12.525s
user 0m1.340s
sys 0m11.077s