SuperPages utilization survey

[Mikolaj Golub]

On Sat, 9 Jun 2012 11:38:22 +0300 Konstantin Belousov wrote:

 KB> On Sat, Jun 09, 2012 at 10:31:17AM +0300, Mikolaj Golub wrote:
 >> 
 >> On Fri, 1 Jun 2012 14:54:48 +0200 Ivan Voras wrote:
 >> 
 >>  IV> On 1 June 2012 14:35, Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl> wrote:
 >>  >>> http://people.freebsd.org/~ivoras/stuff/spsurvey.py
 >> 
 >>  ...
 >> 
 >>  IV> If anyone posts more data, I'll analyse it. I'm more worried about the
 >>  IV> granularity of procstat, where it marks the entire region if a single
 >>  IV> superpage exists in it - it means any such analysis is only
 >>  IV> approximate.
 >> 
 >> Here is a patch (for kernel and procstat) that allows to see amount of pages
 >> mapped to superpages.
 >> 
 >> http://people.freebsd.org/~trociny/procstat-superpages.cnt.1.patch
 >> 
 >> Not sure it is useful enough to be committed.

 KB> Superpage aggregates mappings for several normal-sized pages.
 KB> As a consequence, when you iterate over small pages in
 KB> sysctl_kern_proc_vmmap(), you account each superpage as many time as
 KB> much constituent small pages it contains.

This is exactly what my intention was to count: how much memory are handled by
superpages (using normal-sized page as a measurement unit), not amount of
superpages. And I think this is what Ivan wanted to know. Do you think it is
better to return number of superpages?

-- 
Mikolaj Golub