RE: optimize __gp location

Chen, Kenneth W
2005-01-25T19:57:53Z

>>>>> On Tue, 25 Jan 2005 11:44:34 -0800, "Chen, Kenneth W" said:
Ken> I don't have any benchmark result off hand. But digging through recent
Ken> data, for a well known db benchmark, GOT table access account to about
Ken> 4% of total memory latency in the kernel.

David Mosberger wrote on Tuesday, January 25, 2005 11:52 AM
>
> 4% actual CPU stalls or 4% of potentially overlapped stalls?
>

4% of total cpu stall cycles. 6% of all memory references (in kernel space).
Though they are very concentrated to a few cache lines.

> I'm not trying to be difficult. It's just that GOT optimizations so
> far haven't really paid off in any significant way in the benchmarks I
> tried. You'd think for some benchmarks it does make a significant
> difference (even just based on a cache-pollution argument), I just
> haven't seen it yet...

No biggy, I want to find out myself too whether this has any real impact
or not :-)

- Ken