Re: I would like to see ReiserFS V3 enter a feature freeze real soon.

[Chris Mason]

On Tue, 2004-06-01 at 13:02, Hans Reiser wrote:

> > I can't promise that I'll never making another
> >change in there, but my goal is to keep them to a minimum.
> >
> >  
> >
> >>Also, I would like to see some serious benchmarks of the bitmap 
> >>algorithm changes before they go in.  They seem nice in theory, and some 
> >>users liked them for their uses, but that does not make a serious 
> >>scientific study.  Such a study has a high chance of making them even 
> >>better.;-)
> >>
> >>
> >>
> >
> >Some benchmarks have been posted on reiserfs-list, but I'd love to
> >coordinate with you on getting some mongo numbers. 
> >
> Ok.

> >A good start would be to just rebenchmark against v4.
> >  
> >
> V4 performance is not at a stable point at the moment I think, I have 
> not been monitoring things closely due to trying to earn bucks 
> consulting, and performance did not get tested every week, but there 
> have been reports of performance decreasing and no reports of anyone 
> investigating it, so I need to
> 

Sure, since v4 is being done again -mm right now (right?) you can just
benchmark against a few of the new options.  mount -o alloc=skip_busy
will give you the old allocator.

> Elena, please compose a URL consisting of past benchmarks of various V4 
> snapshots and send it to me.  (I did not read the last one you sent, 
> sorry about that, so include the contents of that one also).
> 
> If the objective is to determine if the algorithm is good, then we 
> should test it with only the algorithm in question changed.
> 
> I would be quite happy to add the algorithm to V4 (or Chris and Jeff can 
> do that) and test it on vs. off.

The algorithm has a few key components, but v4 doesn't need most of it. 
The part to inherit packing localities down the chain would be most
interesting in v4.

The rest approximates things v4 should already be good at, like grouping
some of the metadata near the data blocks.

-chris

Re: I would like to see ReiserFS V3 enter a feature freeze real soon.

[Hans Reiser]

Chris Mason wrote:
On Mon, 2004-05-31 at 12:48, Hans Reiser wrote:
 

While I like and appreciate the data journaling stuff, and I think it 
should go in, real soon now I think we should avoid adding new features 
to V3.  Let the mission critical server folks have a reiserfs version 
that only gets bug fixes added to it, and let V4 be for those who want 
excitement.

Are there any things which Chris and Jeff think should go in besides 
data journaling/ordering and bitmap algorithm changes?

   

We've got io error fault tolerance that needs to go in after the barrier
code has stabilized. 

Ok, this qualifies as bug fixing or close enough.;-)
I can't promise that I'll never making another
change in there, but my goal is to keep them to a minimum.
 

Also, I would like to see some serious benchmarks of the bitmap 
algorithm changes before they go in.  They seem nice in theory, and some 
users liked them for their uses, but that does not make a serious 
scientific study.  Such a study has a high chance of making them even 
better.;-)

   

Some benchmarks have been posted on reiserfs-list, but I'd love to
coordinate with you on getting some mongo numbers. 

Ok.
I can spout off a
long list of places where the code does better then the original v3
allocator, but that's because those were the ones I was trying to fix
;-)
 

zam, I view you as the block allocator maintainer, please review that 
bitmap code from Chris.

Chris and Jeff, can you propose a benchmarking plan for the bitmap code?
   

A good start would be to just rebenchmark against v4.
 

V4 performance is not at a stable point at the moment I think, I have 
not been monitoring things closely due to trying to earn bucks 
consulting, and performance did not get tested every week, but there 
have been reports of performance decreasing and no reports of anyone 
investigating it, so I need to

Elena, please compose a URL consisting of past benchmarks of various V4 
snapshots and send it to me.  (I did not read the last one you sent, 
sorry about that, so include the contents of that one also).

If the objective is to determine if the algorithm is good, then we 
should test it with only the algorithm in question changed.

I would be quite happy to add the algorithm to V4 (or Chris and Jeff can 
do that) and test it on vs. off.

Zam, place that on your todo list and send the todo list to me
-chris