Re: effect of nfs blocksize on I/O ?

[Trond Myklebust]

>>>>> " " == Frank Cusack <fcusack@xxxxxxxxxxx> writes:

    >> OTOH, bsize is of informational interest to programs that wish
    >> to optimize I/O throughput by grouping their data into
    >> appropriately sized records.

     > So then isn't the optimal record size 8192 for r/wsize=8192?
     > Since the data is going to be grouped into 8192-byte reads and
     > writes over the wire, shouldn't bsize match that?  Why should I
     > make 16x 512-byte write() syscalls (if "optimal" I/O size is
     > bsize=512) instead of 1x 8192-byte syscall?

Yes. It is already on my list of bugs.

We basically need to feed 'wtpref' (a.k.a. 'wsize') into the f_bsize,
and 'wtmult' into f_frsize.

OTOH, the s_blocksize (and inode->i_blkbits) might well want to stay
with wtmult.

Cheers,
  Trond
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