RE: optimize __gp location

From: Chen, Kenneth W <kenneth.w.chen_at_intel.com>
Date: 2005-01-26 06:57:53
>>>>> 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


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Received on Tue Jan 25 15:01:24 2005

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