From: Prashant Srinivasan <Prashant.Srinivasan@...>
Date: 2008-04-24T05:23:03+09:00
Subject: Re: [PATCH] SPARC architecture optimizations

Charles Oliver Nutter wrote:
> Prashant Srinivasan wrote:
>> Charles Oliver Nutter wrote:
>>> Prashant Srinivasan wrote:
>>>> Hello Matz,
>>>>
>>>> Thank you for the response.
>>>>
>>>> Yes, it is indeed okay to remove that particular invocation to 
>>>> FLUSH_REGISTER_WINDOWS, since it is redundant.  Another call to 
>>>> FLUSH_REGISTER_WINDOWS is made in rb_thread_save_context as a part 
>>>> of THREAD_SAVE_CONTEXT.
>>>> ie., in rb_thread_save_context(), the following exists.
>>>
>>> So has this been included? I saw some perf numbers relating to this 
>>> and the gains were pretty substantial.
>>
>> Hey Charlie,
>> The above mentioned change has not made it in . . . but another flush 
>> call(the one in EXEC_TAG) has been removed.  It'll be really cool if 
>> someone can commit this  change - the call to flush windows here is 
>> unnecessary - and it's quite an expensive call to have redundant 
>> invocations.
>
> Maybe if you could quantify expensive with some before/after numbers?
>

Here is data obtained from running the Computer language shootout tests 
on a V490 running OpenSolaris.  A couple of tests are home grown.   
We're seeing between 4.88% - 12.74% increase in performance(ie., a 
decrease in latency) with Ruby patched with the flush patch I sent on 
this thread.

TraverseXmlDom 4.88%
SpectralNorm 6.18%
BinaryTrees 6.59%
ParseXmlData 4.41%
Nsievebits 7.44%
Nsieve 1.46%
Fasta 8.11%
Recursive 7.62%
PartialSums 6.44%
Nbody 6.59%
SumCol 12.74%
Fannkuch 7.12%


Cheers,
 -ps

> - Charlie
>


-- 
Prashant Srinivasan
F/OSS Enthusiast
Sun Microsystems, Inc.
http://blogs.sun.com/prashant
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