Re: [PATCH 0/8] v2 De-Couple sysfs memory directories from memory sections

Robin Holt
2010-09-29T19:28:33Z

On Tue, Sep 28, 2010 at 01:17:33PM -0500, Nathan Fontenot wrote:
> On 09/28/2010 07:38 AM, Robin Holt wrote:
> > I was tasked with looking at a slowdown in similar sized SGI machines
> > booting x86_64. Jack Steiner had already looked into the memory_dev_init.
> > I was looking at link_mem_sections().
> >
> > I made a dramatic improvement on a 16TB machine in that function by
> > merely caching the most recent memory section and checking to see if
> > the next memory section happens to be the subsequent in the linked list
> > of kobjects.
> >
> > That simple cache reduced the time for link_mem_sections from 1 hour 27
> > minutes down to 46 seconds.
>
> Nice!
>
> >
> > I would like to propose we implement something along those lines also,
> > but I am currently swamped. I can probably get you a patch tomorrow
> > afternoon that applies at the end of this set.
>
> Should this be done as a separate patch? This patch set concentrates on
> updates to the memory code with the node updates only being done due to the
> memory changes.
>
> I think its a good idea to do the caching and have no problem adding on to
> this patchset if no one else has any objections.

I am sorry. I had meant to include you on the Cc: list. I just posted a
set of patches (3 small patches) which implement the cache most recent bit
I aluded to above. Search for a subject of "Speed up link_mem_sections
during boot" and you will find them. I did add you to the Cc: list for
the next time I end up sending the set.

My next task is to implement a x86_64 SGI UV specific chunk of code
to memory_block_size_bytes(). Would you consider adding that to your
patch set? I expect to have that either later today or early tomorrow.

Robin