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-boun...@openjdk.java.net [mailto:jdk7-dev-
boun...@openjdk.java.net] On Behalf Of Paul Hohensee
Sent: Monday, April 11, 2011 2:01 PM
To: jdk7-dev@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
