review (S) for 6978249: spill between cpu and fpu registers when those moves are fast

[Hiroshi Yamauchi]

Hi Tom,

I'm just curious - how much win is this spilling technique?

Hiroshi

On Thu, Aug 19, 2010 at 2:05 PM, Tom Rodriguez <tom.rodriguez at oracle.com> wrote:
>
> On Aug 19, 2010, at 1:49 PM, David Dabbs wrote:
>
>>
>> Tom Rodriguez wrote:
>>
>> --8< snip
>> [in addition to the register spilling changes]
>> I also moved the logic for PrintFlagsFinal since the initialization of
>> several subsystems may change some flag values which will be missed by
>> the current location.  Tested with scimark, ctw and the nsk tests on
>> 32 and 64 bit.
>>
>>
>> Does the "bundling" of the PrintFlagsFinal tweaks with the spilling mods
>> mean the former won't make it into JDK6 until HS19 lands there?
>
> Yes.  They could always be backported separately under a new bug id.  At the time it didn't seem worth a new bug id.
>
>>
>>
>> Thank you,
>>
>> David
>>
>>
>> p.s. Would this be the right list to post questions regarding HS flags
>> appropriate for
>> maximizing HotSpot performance on Nehalem CPUs?
>
> Yes it would be fine to ask about that here.  Mostly we autodetect and use the appropriate settings so there's not a lot which is or should be tuned.
>
> tom
>
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