
> > Out of interest these are the tentative figures I got with a modified version of the iozone benchmark on my eval board (MPC8260, I & D caches off, 40MHz system clock, 1Mbyte file):
> > 
> > IOZONE performance measurements: 624152 bytes/second for writing the file 2330168 bytes/second for reading the file
> 
> Is this with the default block size?  I would be curious to see the
> impact of
> increasing it. It should lower the relative overhead of scanning the
> block lists.
>  

Yes, that was with IMFS_MEMFILE_BYTES_PER_BLOCK set to 128.  Changing it to 512 does pretty much double the write speed (see below).  

Andy




        IOZONE: Performance Test of Sequential File I/O  --  V1.14 (1/23/92)
                By Bill Norcott

        Operating System: POSIX 1003.1-1988

        Send comments to:       norcott_bill@tandem.com

        IOZONE writes a 1 Megabyte sequential file consisting of
        2048 records which are each 512 bytes in length.
        It then reads the file.  It prints the bytes-per-second
        rate at which the computer can read and write files.


Writing the 1 Megabyte file, 'iozone.tmp'...0.820000 seconds
Reading the file...0.350000 seconds

IOZONE performance measurements:
        1278751 bytes/second for writing the file
        2995931 bytes/second for reading the file

The test completed too quickly to give a good result
You will get a more precise measure of this machine's
performance by re-running IOZONE using the command:

        iozone 17       (i.e., file size = 17 megabytes)



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