Re: Reiser4 unlink performance

[Alec H. Peterson]

Hi Hans,

On Feb 28, 2006, at 12:11, Hans Reiser wrote:
Please describe it in more detail.

Well, the error I'm getting is this:

Feb 21 13:10:22 ecbuild-10 kernel: WARNING: Flushing like mad: 16384

The C program I'm running to do the test is this:

main(int argc, char **argv)
{
  char buf[1024];
  char dir[1024];
  int i,j,k;
  int ret;
  int fd;
  int *sequence;
  struct timeval start, unlinktime, end;

  if(argc != 2)
  {
    fprintf(stderr, "Usage: %s <base directory>\n", argv[0]);
    exit(1);
  }

  strncpy(dir, argv[1], 1024);

  if(chdir(dir))
  {
    perror("chdir");
    exit(1);
  }

  for(i = 0; i < 256; i++)
  {
    snprintf(buf, 1024, "%d", i);
    ret = mkdir(buf, S_IRWXU);
    if(ret && (errno != EEXIST))
    {
      perror("mkdir");
      exit(1);
    }
  }


  {
    sequence = sequence20000;
    gettimeofday(&start, NULL);
    fprintf(stderr, "Starting %d run %d.%d.\n",
            256 * 20000, start.tv_sec, start.tv_usec);

    for(i = 0; i < 256; i++)
    {
      for(j = 0; j < 20000; j++)
      {
        snprintf(buf, 1024, "%d/%d", i, j);
        fd = open(buf, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
        if(fd == -1)
        {
          perror("open");
          exit(1);
        }
        close(fd);
      }
      fprintf(stderr, "Done %d\n", i);
    }

    gettimeofday(&unlinktime, NULL);
    fprintf(stderr, "Starting %d unlink %d.%d, elapsed time was %d.\n",
            256 * 20000, unlinktime.tv_sec, unlinktime.tv_usec,
            unlinktime.tv_sec - start.tv_sec);

    for(i = 0; i < 20000; i++)
    {
      for(j = 0; j < 256; j++)
      {
        snprintf(buf, 1024, "%d/%d", j, sequence[i]);
        unlink(buf);
        if(fd == -1)
        {
          perror("unlink");
          exit(1);
        }
      }
      fprintf(stderr, "Done %d\n", i);
    }

    gettimeofday(&end, NULL);
    fprintf(stderr, "Done with %d unlink %d.%d, elapsed time was %d. 
\n",
            20000 * 256, end.tv_sec, end.tv_usec,
            end.tv_sec - unlinktime.tv_sec);
  }

  exit(0);
}

sequence20000 is an array which contains a sequence from 1 to 20000  
randomly ordered.

Alec