[Pvfs2-developers] Patches: (1) fixing incorrect small I/O total_size, (2) processing multiple aiocbs at a time

[Robert Latham]

On Thu, May 18, 2006 at 05:06:04PM -0600, Avery Ching wrote:
> You're right that this might affect other stuff.  I think I guess the
> encode and decode functions will need to be changed.  Okay, fixed.  I've
> attached another patch that does this and changes it to PVFS_size.  I
> think that's it hopefully...

cool. committed that
> 
> > > process_multiple_aiocbs.patch:
> > > 
> > > Fixed the dbpf_bstream_listio_convert() function to actually handle more
> > > than a single aiocb at a time.  This should boost noncontiguous I/O
> > > performance quite a bit.
> > 
> > Can you help me understand why your changes work?  What is making the
> > existing code return too early?   I'm not saying you did it wrong, of
> > course.  it's just code i don't know very well.
> > 
> 
> In most cases (actually all that I know of) mem_count = 1.  This means
> that when it passes through the while loop it breaks out even if it
> isn't finished since it is oom.  Therefore it was only doing a single
> aiocb at a time.  By changing the break conditional and updating the
> cur_mem_size and cur_stream_size, we can see where we really need to
> break out of the while loop (when it is oos or oom AND there are no
> bytes left in the current piece).  Hope that helps!

it does indeed. committed that too.

==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Labs, IL USA                B29D F333 664A 4280 315B