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Re: Don't be too quick to assume that -XX:+UseCompressedOops is a good thing
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Re: Don't be too quick to assume that -XX:+UseCompressedOops is a good thing



Vs. just guessing about stuff:

http://wikis.sun.com/display/HotSpotInternals/CompressedOops
http://blog.juma.me.uk/2008/10/14/32-bit-or-64-bit-jvm-how-about-a-hybrid/

On Wed, Apr 28, 2010 at 9:38 AM, Benson Margulies <email@hidden> wrote:
> About a 30% reduction in speed in the viterbi decoder of some code that
> segments Chinese text. Hard numbers.
> I haven't had time to make dueling jprofiler results and compare them. This
> code does relentlessly use primitive types for speed, but it also has plenty
> of String's floating around.
>
> On Wed, Apr 28, 2010 at 8:15 AM, Erik Mattheis <email@hidden> wrote:
>>
>> Can you post some details? I haven't done any serious benchmarking, but I
>> haven't seen a scenario where something 'seemed' significantly slower, and
>> in all cases I've tried (GUI applications and J2EE applications) the memory
>> footprint was significantly smaller). I imagine a codebase that would not
>> benefit much from compressed OOPs would be one relying primarily on
>> manipulating primitive data types, but in that scenario I don't see how
>> performance would be impacted. I'd love to see your data, and if anyone has
>> some insight on the potential performance tradeoffs with compressed OOPs,
>> please share!
>>
>> --
>> Erik
>>
>>
>> On Apr 26, 2010, at 9:30 PM, Benson Margulies wrote:
>>
>> > A quick benchmark of some CPU-intensive code of ours shows a quite
>> > marked slowdown with that option turned on.
>>
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References: 
 >Don't be too quick to assume that -XX:+UseCompressedOops is a good thing (From: Benson Margulies <email@hidden>)
 >Re: Don't be too quick to assume that -XX:+UseCompressedOops is a good thing (From: Erik Mattheis <email@hidden>)
 >Re: Don't be too quick to assume that -XX:+UseCompressedOops is a good thing (From: Benson Margulies <email@hidden>)



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