Re: big ext3 sequential write improvement in 2.5.51-mm1 gone in 2.5.53-mm1?

[Andrew Morton <akpm@digeo.com>]

rwhron@earthlink.net wrote:
>
> Did you add a secret sauce to 2.5.59-mm2?

I have not been paying any attention to the I/O scheduler changes for a
couple of months, so I can't say exactly what caused this.  Possibly Nick's
batch expiry logic which causes the scheduler to alternate between reading
and writing with fairly coarse granularity.

>  10x sequential write improvement on ext3 for multiple tiobench threads.

OK...  

I _have_ been paying attention to the IO scheduler for the past few days. 
-mm5 will have the first draft of the anticipatory IO scheduler.  This of
course is yielding tremendous improvements in bandwidth when there are
competing reads and writes.

I expect it will take another week or two to get the I/O scheduler changes
really settled down.  Your assistance in thoroughly benching that would be
appreciated.

> 2.4.20aa1     8.24  7.21%    28.587   449134.11  0.10395  0.07086    114
> 2.5.59        9.50  5.50%    36.703     4310.62  0.00000  0.00000    173
> 2.5.59-mm2   35.28 17.69%    10.173    18950.56  0.01010  0.00000    199

boggle.