SuperPages utilization survey

[Florian Smeets]

On 05.06.12 16:29, Mark Felder wrote:
> On Sat, 02 Jun 2012 06:49:18 -0500, Florian Smeets <flo at freebsd.org> wrote:
> 
>> As far as i understand it does at least enable usage of pages up to 4MB,
>> perhaps someone should teach mysql about the FreeBSD's limits?
>> If you look at the output i sent, it certainly changes from using no
>> superpage mappings at all to using them to some degree, if you script
>> can be trusted
> 
> Wow, this is a nice find. If someone were to add a patch for FreeBSD's  
> superpages we might be able to get a nice little performance boost with  
> little effort. Even the increase to 4MB for now is a welcome improvement.  
> I'll make sure to put this in my toolbox....

I played with this some more. MySQL does not seem to use superpages.
After a mysqld restart Ivan's script and procstat showed superpage
mappings for mysqld, but it seems once MySQL "touches" the memory it's
not in superpages anymore. I looked at the MySQL code a bit and one
would need to add FreeBSD support in a couple of places. Perhaps I'll
find some time to try this, but i cannot make any promises.

Florian

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