malloc - cache locality - TLB

[Rich Felker]

On Fri, Dec 20, 2013 at 08:00:51PM +0100, Ondřej Bílka wrote:
> On Fri, Dec 20, 2013 at 11:21:16AM -0500, Rich Felker wrote:
> > On Fri, Dec 20, 2013 at 05:09:15PM +0100, Ondřej Bílka wrote:
> > > As linux supported since 2003 huge pages we could try to use these.
> > 
> > Transparentt huge pages are the only sane way to use them, and they're
> > already supported for huge malloc calls serviced by mmap.
> 
> This needs to invoke libhugetlbfs which is extra dependency. A
> transparency is not wanted as we need to distinguish cases where these
> pages will be used versus where not.

No it doesn't. That's the old, nasty, should-be-deprecated
non-transparent way. With transparent huge pages enabled in the
kernel, the kernel simply uses them when you call mmap without
userspace ever having to be aware of it.

Rich