Re: [Ext2-devel] Re: Latest ext3 patches (extents, mballoc, delayed allocation)

[Mingming Cao <cmm@us.ibm.com>]

Alex Tomas wrote:

> Good day all, 
> 
> I've updated the patchset against 2.6.10. A bunch of bugs have been
> fixed and mballoc now behaves smarter a bit. Extents and mballoc 
> patches collects some stats they print upon umount. NOTE: they must
> not be used to store important data. A lot of things are to be done.
> 

Thanks Alex, for the hard work.

> Please review. Any comments and suggestions are very welcome.

Will do.

> 
> 
> The followins crazy listing shows tiobench's results for SMP box:
> 
> Random Reads
>                               File  Blk   Num                   Avg     CPU
> Identifier                    Size  Size  Thr   Rate  (CPU%)  Latency   Eff
> ---------------------------- ------ ----- ---  ------ ------ --------- -----
> ext2                          512   4096    1  119.05 40.37%     0.031   295
> ext3                          512   4096    1  134.78 37.08%     0.028   363
> ext3rs                        512   4096    1   25.18 8.377%     0.154   301

The throughput here is really weird. Reservation code does not touch 
read code path. I could imagine that it maybe change the disk layout and 
make a difference on sequential reads, but I am not sure how it will 
affect the random read. And this is happening on 1 thread and 4 threads, 
but for 2 threads, reservation case is the best. I will see if I could 
repeat the same results here.

Mingming