RFR [9]: 8050142: Optimize java.util.Formatter

[Claes Redestad]

Hi Peter,

On 2014-07-14 14:05, Peter Levart wrote:
> On 07/14/2014 01:29 PM, Claes Redestad wrote:
>> Hi Peter,
>>
>> On 2014-07-14 13:25, Peter Levart wrote:
>>> On 07/14/2014 12:07 PM, Claes Redestad wrote:
>>>> Hi,
>>>>
>>>>  please review this patch which optimizes away some allocations 
>>>> from java.util.Formatter and achieve 1.1-1.3x speedups of micros 
>>>> targetting String.format. See bug for more details.
>>>>
>>>>  webrev: http://cr.openjdk.java.net/~redestad/8050142/webrev.0
>>>>  bug: https://bugs.openjdk.java.net/browse/JDK-8050142
>>>>
>>>>  Testing: JPRT, jtreg (java/lang/String, java/util/Formatter), 
>>>> SPECjbb2013 and microbenchmarks
>>>>
>>>>  Thanks!
>>>>
>>>>  /Claes
>>>
>>> Hi Claes,
>>>
>>> Since justify() result is always appended to the resulting 
>>> Appendable, you could merge the functionality and eliminate 
>>> constructing intermediary StringBuilder altogether:
>>>
>>> http://cr.openjdk.java.net/~plevart/jdk9-dev/Formatter/webrev.01/
>>>
>> Looks good, especially eliminating the need for two different append 
>> methods. I'll update based on this and other suggestions.
>>
>> /Claes
>>> Regards, Peter
>>
> Hi Claes,
>
> If you're in a really hyper-optimizing mood, you could also eliminate 
> construction of ArrayList in parse():
>
> http://cr.openjdk.java.net/~plevart/jdk9-dev/Formatter/webrev.02/
>

Have you measured this to have a real effect? I'm not convinced it would 
matter enough to warrant the extra complexity of turning FormatString 
into a linked list. I feel this patch is already a bit saturated with 
different small optimizations - maybe should deal with this in a new RFE?

/Claes
> Regards, Peter
>