Re: Large Partition Performance Test

[Oleg Drokin <green@namesys.com>]

Hello!

On Thu, Apr 11, 2002 at 11:14:59AM -0700, Bill Rees wrote:
> I upgraded my kernel to 2.4.19-pre6 with the speedup
> patch installed and still see similiar results as
> before.  As the amount of data on the partition
> increases, my write performance slows.  This time, I
> simply modified a previously posted script to mimic my
> production application.  The test is still running and
> will take quite awhile to fill the disk.  Each line of
> the output represents 1.68gb of disk space.

Ok, I see the problem now. You create a lot of small files, and when a lot
of disk space is used, a lot of unnecesary blockfinding is performed on
each file creation.
if you mount your partition with -o no_unhashed_relocation option,
effect of that will be much lighter. With this option that's what I see:
day/hour 00 00 seconds = 285
day/hour 00 01 seconds = 288
day/hour 00 02 seconds = 290
day/hour 00 03 seconds = 289
day/hour 00 04 seconds = 290
day/hour 00 05 seconds = 292
day/hour 00 06 seconds = 292
day/hour 00 07 seconds = 292


Also new block allocator that I posted to the list recently should not excibit
this behavior at all in any of modes. (I am just going to verify this theory ;)
)

Bye,
    Oleg