RFR: 8203410: Zero: Disable jfr feature by default

[Severin Gehwolf]

Hi Erik,

On Fri, 2018-05-18 at 08:41 -0700, Erik Joelsson wrote:
> The change makes sense, but I think I would prefer if the conditional 
> was based on jvm variant rather than the target cpu, like this:
> 
> if ! HOTSPOT_CHECK_JVM_VARIANT(zero); then

Thanks for the review!

New webrev:
http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8203410/webrev.02/

Cheers,
Severin

> /Erik
> 
> 
> On 2018-05-18 06:57, Severin Gehwolf wrote:
> > Hi,
> > 
> > Currently the jfr (Flight Recorder) feature is being built by default
> > for Zero JVMs. However, it's not clear whether there will be jfr
> > support for the Zero variant JVM. At this point, when
> > StartFlightRecording option is being used for a Zero JVM it
> > asserts/crashes. It seems more appropriate to disable the feature for a
> > default build and require one to enable the feature explicitly via:
> > 
> > configure --with-jvm-feature=jfr --with-jvm-variants=zero
> > 
> > We can revisit this change of default once there is good Zero+JFR
> > support, which currently isn't the case.
> > 
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8203410
> > webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8203410/webrev.01/
> > 
> > Testing: Verified that the StartFlightRecording option is unrecognized
> > for a default --with-jvm-variants=zero build.
> > 
> > Thoughts?
> > 
> > Thanks,
> > Severin
> 
>