[PATCH][Review Requested][Compilation Time] Calculate hash value and equality comparison within SCEV node itself

[Duncan Sands]

Hi Ram, I'm convinced, thanks for doing the additional testing.

Ciao, Duncan.

PS: That said, you should really also include the number of runs, but hey!

On 06/02/13 23:32, Murali, Sriram wrote:
> Hi Duncan,
> I reran the tests several times to obtain the standard deviation, and found that there is little to no deviation in the runs
>
> without patch	with patch	improvement
> avg	stdev	avg	stdev	
> 14.73	0.05	14.31	0.14	2.89
> 14.59	0.29	13.99	0.09	4.14
> 15.92	0.18	15.36	0.17	3.48
> 18.75	0.19	18.32	0.29	2.33
> 15.40	0.16	15.08	0.11	2.07
> 17.22	0.13	16.98	0.26	1.40
> 18.46	0.06	18.32	0.53	0.79
> 17.07	0.06	16.76	0.29	1.82
> 13.55	0.12	12.94	0.23	4.46
> 17.53	0.18	17.63	0.27	-0.61
> 16.37	0.09	16.27	0.36	0.60
> 12.09	0.02	11.85	0.22	2.05
> 8.36	0.08	8.14	0.12	2.54
> 12.82	0.04	12.76	0.16	0.52
> 28.79	0.27	27.49	0.42	4.52
> 4.89	0.04	4.89	0.18	-0.02
> 22.04	0.11	21.52	0.55	2.38
> 9.18	0.12	8.81	0.17	4.06
> 7.78	0.12	7.69	0.23	1.08
>
> Thanks
> Ram
>
> -----Original Message-----
> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Duncan Sands
> Sent: Tuesday, February 05, 2013 10:39 AM
> To: llvm-commits at cs.uiuc.edu
> Subject: Re: [PATCH][Review Requested][Compilation Time] Calculate hash value and equality comparison within SCEV node itself
>
> Hi Sriram,
>
> On 04/02/13 20:39, Murali, Sriram wrote:
>> SCEV is currently implemented as a FoldingSetNode to calculate the
>> hashing value and for equality comparison. This causes some
>> performance loss. This patch aims at improving the compilation time
>> performance by implementing the hashing and equality comparison within
>> SCEV class instead of inheriting FoldingSetNode. The compilation performance gain for this particular refactoring is around 2%.
>
> sorry to be a pain, but such numbers are meaningless without an estimate of the variance.  In short, are the apparent differences statistically significant, or might they just be random noise?
>
> Ciao, Duncan.
>
>>
>> This patch is part of a series of compile time improvements. Although
>> these were originally produced by our colleague Wan Xiaofei, our team
>> consisting of tyler.nowicki at intel.com
>> <mailto:tyler.nowicki at intel.com>; preston.gurd at intel.com
>> <mailto:preston.gurd at intel.com>; and sriram.murali at intel.com <mailto:sriram.murali at intel.com>, are assuming all responsibility for this work.
>>
>> Please Review
>>
>> Thanks
>>
>> Sriram Murali
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