Proposal: MaxTenuringThreshold and age field size changes

kirk kirk.pepperdine at gmail.com
Thu May 29 00:16:23 PDT 2008


Thomas Viessmann wrote:
> Just my two cents:
>
> > (out of curiosity: does anyone actually use -XX:+NeverTenure?)
>
> No, I wasn't even aware of this flag.
>
> > If MTT is set by the user to a value > max age, we will actually set 
> it to max age.
>
> Agree. Still most customers use 32.
>
>> how many people on the list missed the age-bit that vanished across 
>> the 5u5->5u6 transition and wished the bit were back?
>
> Actually most if not all customers missed that change. I always see
> 32 or 0. Nothing in between. Customers typically just enable or disable
> survivor spaces and do not care about the 4 or 5 bit granularity of
> MaxTenuringThreshold
>
>
>
This is mostly because there isn't a well known tool that will suggest a 
change in the MTT. IMHO, having lower MTT values is less useful than 
having higher ones. I rarely want to prematurely promote where as I 
often would like to delay promotion.

Kind regards,
Kirk Pepperdine



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