Bogofilter simulator.

[Greg Louis]

On 20030204 (Tue) at 0042:04 +0100, Matthias Andree wrote:
> Greg, other interested parties,
> 
> I have a program that simulates the access pattern our bogofilter
> problem performs; while it is not exactly the same distribution (it's
> slightly more homogenous in respect to frequencies), and I haven't
> compared \chi^2 or something, but I find it good enough:
> 
> ext3 + SCSI    -> fast, 24 s (aic7880 + fujitsu mah3182mp)
> reiserfs + IDE -> fast, 23 s (via686  + ibm djna-352030)
> ext3 + ide     -> slow, >8 min (via 686 + ibm dtla-307045)
> 
> Please try if you can reproduce your bad bogofilter times with this
> program and let me know -- I want to be sure this works before we pass
> this to Stephen and Andrew on the ext3 users list. To use:

Sorry -- just saw this now, I wasn't online long enough yesterday. 
I've replied to you and Andrew and the ext3 list:
ext3 + scsi - slow (7 min 13 sec)
ext3 + ide -  slow (8 min 14 sec)

My original data=ordered/journal/writeback comparison was done on scsi,
so I guess conditions on my (old) scsi drive are capable of triggering
the regenerative slowdown.

I suspect I have info on comparing "random" distributions but I'll have
to dig for it.  I'll let you know if I find something.

-- 
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