Re: making use of large TLB pages

Neil Conway wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Is TLB Linux-only?
>
> Well, the "TLB" is a feature of the CPU, so no. Many modern processors
> support large TLB pages in some fashion.
>
> However, the specific API for using large TLB pages differs between
> operating systems. The API I'm planning to implement is the one
> provided by recent versions of Linux (2.5.38+).
>
> I've only looked briefly at enabling the usage of large pages on other
> operating systems. On Solaris, we already use large pages (due to
> using Intimate Shared Memory). On HPUX, you apparently need call
> chattr on the executable for it to use large pages. AFAIK the BSDs
> don't support large pages for user-land apps -- if I'm incorrect, let
> me know.
>
> > Why use it and non SysV memory?
>
> It's faster, at least in theory. I posted these links at the start of
> the thread:
>
> http://lwn.net/Articles/6535/
> http://lwn.net/Articles/10293/
>
> > Is it a lot of code?
>
> I haven't implemented it yet, so I'm not sure. However, I don't think
> it will be a lot of code.

OK, personally, I would like to see an actual speedup of PostgreSQL
queries before I would apply such a OS-specific, version-specific patch.

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