31 messages in org.codehaus.groovy.devRe: [groovy-dev] as usual on performa...
FromSent OnAttachments
Alex TkachmanFeb 27, 2008 5:38 am 
Guillaume LaforgeFeb 27, 2008 5:47 am 
Alex TkachmanFeb 27, 2008 6:01 am 
Chanwit KaewkasiFeb 27, 2008 6:21 am 
Martin C. MartinFeb 27, 2008 6:27 am 
Jochen TheodorouFeb 27, 2008 6:32 am 
Jochen TheodorouFeb 27, 2008 6:33 am 
tugwilsonFeb 27, 2008 6:55 am 
Chanwit KaewkasiFeb 27, 2008 7:15 am 
Chanwit KaewkasiFeb 27, 2008 8:01 am 
Jochen TheodorouFeb 27, 2008 8:28 am 
tugwilsonFeb 27, 2008 9:00 am 
tugwilsonFeb 27, 2008 9:55 am 
Chanwit KaewkasiFeb 27, 2008 11:27 am 
Chanwit KaewkasiFeb 27, 2008 11:31 am 
Jochen TheodorouFeb 27, 2008 11:36 am 
Alex TkachmanFeb 27, 2008 11:58 am 
Martin C. MartinFeb 27, 2008 12:18 pm 
Jochen TheodorouFeb 27, 2008 12:37 pm 
Jochen TheodorouFeb 27, 2008 12:45 pm 
tugwilsonFeb 27, 2008 12:48 pm 
tugwilsonFeb 27, 2008 12:51 pm 
Martin C. MartinFeb 27, 2008 1:27 pm 
Alex TkachmanFeb 27, 2008 1:48 pm 
tugwilsonFeb 27, 2008 2:14 pm 
Jochen TheodorouFeb 27, 2008 5:09 pm 
Alexandru Popescu ☀Feb 27, 2008 5:38 pm 
Charles Oliver NutterFeb 28, 2008 12:20 am 
Jochen TheodorouFeb 28, 2008 1:33 am 
Alexandru Popescu ☀Feb 28, 2008 2:56 am 
tugwilsonFeb 28, 2008 3:29 am 
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Subject:Re: [groovy-dev] as usual on performance - operations on primitivesActions...
From:tugwilson (tu@wilson.co.uk)
Date:Feb 27, 2008 2:14:51 pm
List:org.codehaus.groovy.dev

Martin C. Martin-2 wrote:

tugwilson wrote:

Jochen Theodorou wrote:

tugwilson schrieb: [...]

The main execution cost is fetching the MetaClass for b (Ng wraps ints in NgInt which has a getMetaClass method rather than Integer which requires a registry lookup), a check to see if a Category has changed the plus operation on int and a check that the plus operation on int has not been monkey patched. These costs are exactly equivalent to your "Integer#plus(Integer) is default" check, except the cost of getting the MetaClass for Integer is higher in Groovy.

well... theoretically it is enough to reuse that check for a certain amount of actions... for example:

int j=0; for (int i=0; i<n i++) { j+=i }

In this case we could check the MetaClass for Integer and if it is not modified, we could execute the code in its static form. This means for all n nest() calls and all n plus class we have only a single MetaClass check.

Checking outside the loop?

If so you're just deliberately breaking the semantics of the language.

I think Jochen's intention is to move a loop invariant outside the loop. The example is so simple and self contained that metaclasses can't change within the loop.

Moving a constant calculation outside a loop is a standard optimization which doesn't change the semantics; I don't think Jochen meant that all loops (or even most loops) could be handled that way.

There's no problem with moving an invariant outside the loop. However this isn't an invariant. another thread can change the behaviour of Integer sop the behaviour of Integer is not guaranteed to be unchanged in the loop body.

John Wilson

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