Embedd bitmaps into dataflow problem structures

[Paolo Bonzini]

On 06/04/2010 03:00 PM, Jan Hubicka wrote:
> Hi,
> dataflow datastructures are quite pointer heavy and since we collect a lot
> of cache misses looking up bitmap headers and most of those are accounted to
> dataflow, I decided to try to reduce amount of indirection here to improve
> locality.
>
> This is first step, putting bitmap into the problem structures as bitmap_headers.
> This saves one pointer and two obstack allocations and does not cost memory since
> we allocate the outer structure always together with all the bitmaps I believe.
>
> cc1 WHOPR build is now 10m38 seconds, before patch I measured always over 10m50
> seconds.

That's 1.5% -- whoa.

This is obviously okay. :-)

> I wonder if someone tested putting the df-problems bitmaps into specific
> obstacks that are deallocated when problem is done?  It might help a bit with
> locality: the main bitmap obstack get completely mixed via freelists very soon.

I thought Steven did that, but the code says he didn't. :-)

> I am also attaching the promised partial inlining bitmap patch.

What's the performance improvement from that?

Paolo