New String-related cmdline options

[Paul Hohensee]

AggressiveOpts does both.  I.e., it turns on new/experimental features 
as well
as just allowing them to be enabled.  Depends on the feature.  Typically,
the set of features enabled by AggressiveOpts can be enabled via individual
switches as well.  Not always, though.   The precise effect of 
AggressiveOpts
depends on what the development team needs it to be.

Note that by its nature, the definition of AggressiveOpts can and will 
change
from release to release.  So while it usually provides a performance boost,
it might not always provide the _same_ performance boost.  I.e., it's not
designed to be consistent from release to release.

Paul

On 4/11/11 4:13 PM, David Dabbs wrote:
>
>> -----Original Message-----
>> From: jdk7-dev-bounces at openjdk.java.net [mailto:jdk7-dev-
>> bounces at openjdk.java.net] On Behalf Of Paul Hohensee
>> Sent: Monday, April 11, 2011 2:01 PM
>> To: jdk7-dev at openjdk.java.net
>> Subject: Re: New String-related cmdline options
>>
>> What 6714404 means is that the +UseStringCache switch only works if you
>> also specify
>> +AggressiveOpts.  By default, UseStringCache is off, even if
>> AggressiveOpts is on, because
>> at the moment it benefits only some applications on some architectures.
>> At some point,
>> we'll probably make whether it defaults on or off platform dependent,
>> but we haven't
>> completed the necessary analysis yet.
>>
>> Recall that AggressiveOpts enables optimizations that we believe will
>> have general
>> applicability, but of which we're not yet confident enough to either
>> make default on
>> or platform-dependent default-on.  We'll almost always do one or the
>> other in some
>> future release, so think of AggressiveOpts as a way-station for new
>> optimizations.
>>
>> Paul
>>
>> On 4/11/11 9:21 AM, David Dabbs wrote:
>>> Hi.
>>>
>>> I see there are some new String-related cmdline opts. StringTableSize
>> and
>>> UseStringCache. Are there docs concerning the new switches and/or
>>> diagnostics related to tuning? Just for grins, I specified
>> AggressiveOpts,
>>> but didn't see UseStringCache set to true, or did I misunderstand
>> this
>>> patch?
>>>
>>>          6714404: Add UseStringCache switch to enable String caching
>> under
>>> AggressiveOpts
>>>
>>>
>>> Thank you,
>>>
>>> David
>>>
> Okay. Your description sounds like UnlockExperimentalVMOptions. I was
> somehow under the impression that specifying AggressiveOpts enabled (as in
> turned on) new/experimental features as opposed to just allowing them to be
> enabled.
>
>
> Thank you Paul.
>
> David
>
>