Re: [PATCH] Clustering indirect blocks in Ext3

Daniel Phillips
2008-01-11T17:05:38Z

On Thursday 10 January 2008 13:17, Abhishek Rai wrote:
> Benchmark 5: fsck
> Description: Prepare a newly formated 400GB disk as follows: create
> 200 files of 0.5GB each, 100 files of 1GB each, 40 files of 2.5GB
> ech, and 10 files of 10GB each. fsck command line: fsck -f -n
> 1. vanilla:
> Total: 11m25.3s
> User: 13.4s
> System: 13.2s
> 2. mc:
> Total: 3m11.0s
> User: 13.1s
> System: 12.9s
>
> Note: I'll report results from kernbench and compilebench shortly.
>
> Observations:
> Sequential write performance is much better with metaclustering than
> with vanilla. To better understand it, I ran the same benchmark with
> the new code but with the metaclustering option turned off and I got
> the same performance as vanilla which makes me believe that there is
> something about metaclustering that helps write performance though I
> don't have a very good handle of what that thing might be.

Your results are very impressive. In my opinion, the sooner this goes
in, the better, since everybody hates waiting for fsck. The only issue
that jumps out at me is, the patch is big and changes a significant
amount of Ext3 code outside of the metacluster path, which is not a bad
thing except that these changes are going to need to be tested fairly
heavily.

The way to do that is, put a big [CALL FOR TESTING] in your subject line
the next time you post, and use an attention-getting subject line
like "Make Ext3 fsck way faster". Diff the patch against the latest
stable kernel to make things as easy as possible for the people who are
hopefully going to download your patch, try it, and report their
results.

The other way is just to ask Andrew to put it in -mm when you feel
ready, but your chances are much better if you already have people
sending in mails saying how great your patch is.

Another thing you might consider is a port to Ext4. After all, the
world has waited this long for your patch, so it can likely survive
waiting a little longer.

You somehow seem to have missed attracting the attention of Jon Corbet,
a rare occurrence for a patch of this significance. With the subject
line modified as above, you are more likely to get the attention you
deserve. Good luck!

Regards,

Daniel