[PVFS-users] terrible performance ... help!

[Kaveh Moallemi]

Hello,

I'm getting terrible performance using pvfs calls ... far worst than
using regular (non-pvfs) IO.  I've provided a code snip below ... does
anyone see something wrong with it?

I'm using PVFS version 1.6.2 with a single iod (for the time being). 
I've noticed that with the non-pvfs version of my program, the iod
runs at about 10% CPU.  And, with the pvfs version, the iod runs in
excess of 80% CPU time!

Thanks for looking,


../kaveh

-------------------------------------------------------------
#include <string.h>
#include <fcntl.h>
#include <pvfs.h>

...

int f3;                         /* PVFS file handle */
char pvfs_buffer[LINE_LENGTH + 1];
char tmp_buffer[21];
struct pvfs_filestat pvfs_f_stat = {
  0,                            /* base iod to start from */
  -1,                           /* iod's to use (use all available) */
  64 * 1024                     /* stripe size (bytes) */
};

...

f3 = pvfs_open (file_out, O_WRONLY | O_CREAT, 0666, &pvfs_f_stat);

...

memset (pvfs_buffer, 0, sizeof (pvfs_buffer));
for (ii = 1; ii <= cc; ii++)
  {
    sprintf (tmp_buffer, "%d ", compsub[ii]);
    strcat (pvfs_buffer, tmp_buffer);
  }
strcat (pvfs_buffer, "\n");
pvfs_write (f3, pvfs_buffer, strlen (pvfs_buffer));

...

pvfs_close (f3);

...