Please review -XshowSettings a java launcher option.
kumar.x.srinivasan at oracle.COM
Thu Nov 11 19:11:51 PST 2010
Hi Mr. Holmes,
> Hi Kumar,
> Is the purpose here to report what command-line options were used or
> to report what particular settings are in effect? If the former then
> you do not need any defaults for the "not set" case. If the latter
> then you should really defer this to the VM itself for the "VM
> options", because as it stands:
Right we need to defer it to the VM, jdk7++ ? I will file an RFE to do
> - if -Xmx is not set then Runtime.maxMemory() is not equivalent, so
> you are misleading the user (And why not report -Xms?)
No one beat me up on Xms so much as Xmx or max memory.:-)
As for memory, IIRC I compared the values that
which reports the same value as I get here.
I will explain some of this in the help document, and maybe put a note
next to one of these
values such as 985M (approx.)
> - if -Xss is not set the resulting value is not an OS default but a VM
In the case of windows the VM has no preference so the launcher defaults
back to the OS,
but if the VM has a pref. then that would be reported, usually *nixes.
> - ServerClassMachine() does not take into account -Xint possibility
> (and will need updating for Tiered compilation)
Absolutely when that becomes a reality.
> I'd be tempted to just drop the "VM options" part of this, unless you
> are going to make a call into the VM to obtain them.
I think I want to have it and put in the necessary VM hooks at a later
stage. It would be
good to get this in and get more feedback and enhance/evolve it in a
> Kumar Srinivasan said the following on 11/12/10 07:56:
>> Hi All,
>> Please review the following:
>> This will print all the known settings/properties/locales
>> supported and known to Java, this has been a long standing request.
>> A sample output attached below.
>> Note: the -X option specifically is being used so we can evolve this
>> and add more useful information, in future versions of java.
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