Re: [00/17] Large Blocksize Support V3

[David Chinner <dgc@sgi.com>]

On Sat, Apr 28, 2007 at 02:36:20AM +1000, David Chinner wrote:
> The test was writing a single 50GB file to a fresh filesystem, and
> then reading it back. Run on two different dm stripes - a 4-disk
> RAID) and a 8disk RAID0 stripe, with a stripe unit of 512k.  Disks
> are 10krpm SAS, external jbod on PCI-X good for ~850MB/s read and
> ~750MB/s write.  Server is 4p intel x86_64 with 16GB RAM.
> 
>                     READ            WRITE
> blksz  disks     tput   sys       tput    sys
> -----  -----    -----   ----      -----  ----
>  4k      4       332     35s      203     76s
> 64k      4       173     20s      273     21s
>  4k      8       403     35s      443     76s
> 64k      8       634     21s      540     21s
> 
> Throughput in MB/s.

Some more information - stripe unit on the dm raid0 is 512k.
I have not attempted to increase I/O sizes at all yet - these test are
just demonstrating efficiency improvements in the filesystem.

These numbers for 32GB files.

                    READ            WRITE
disks  blksz     tput   sys       tput    sys
-----  -----    -----   ----      -----  ----
  1     4k        89     18s       57     44s
  1    16k        46     13s       67     18s
  1    64k        75     12s       68     12s
  2     4k       179     20s      114     43s
  2    16k        55     13s      132     18s
  2    64k       126     12s      126     12s
  4     4k       350     20s      214     43s
  4    16k       350     14s      264     19s
  4    64k       176     11s      266     12s
  8     4k       415     21s      446     41s
  8    16k       655     13s      518     19s
  8    64k       664     12s      552     12s
 12     4k       413     20s      633     33s
 12    16k       736     14s      741     19s
 12    64k       836     12s      743     12s

Throughput in MB/s.


Consistent improvement across the write results, first time
I've hit the limits of the PCI-X bus with a single buffered
I/O thread doing either reads or writes.

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group
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