On 02.06.12 12:48, Ivan Voras wrote:
> On 2 June 2012 12:29, Wojciech Puchar <wojtek@wojt...> wrote:
>>>>
>>>
>>> In my words i would say "It enables mysql to use super-pages/large-pages".
>>
>> i asked the question wrong. the right should be "how does it do". Because i
>> am not aware about any user level interface in FreeBSD to explicitly request
>> superpage mapping.
>
> You are right, there isn't any.
>
> The code in mysqld.cc only works if HAVE_SOLARIS_LARGE_PAGES is defined:
>
> 3229 #endif /* HAVE_LARGE_PAGES */
> 3230 #ifdef HAVE_SOLARIS_LARGE_PAGES
> 3231 #define LARGE_PAGESIZE (4*1024*1024)  /* 4MB */
> 3232 #define SUPER_LARGE_PAGESIZE (256*1024*1024)  /* 256MB */
> 3233   if (opt_large_pages)
> 3234   {
>
> ...
>
> 3278   }
> 3279 #endif /* HAVE_SOLARIS_LARGE_PAGES */
>

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 :)

Florian