JVM flags: product -> manageable ?

[Staffan Larsen]

I don't know how reliable it would be to just make those flags manageable. For example, the GC code may have code paths that set up information for logging at an early point in time only if logging is enabled, and depend on this information being available later. Turning on logging mid-flight could cause problems here. I don't know if this is true, though, but it would have to be examined when making flags manageable.

/Staffan

On 12 mar 2012, at 20:47, Srinivas Ramakrishna wrote:

> Thanks for the prompt response, Staffan!
> 
> One question is re support of existing flags (in particular GC flags) and their toggling via the
> existing jmap interface. I am sure that will be detailed in the JEP in progress.
> In the much shorter term, I was wondering if the step of changing the trivially changeable
> GC-logging flags could be accomplished, since that would really involve a quick audit and some
> really quick performance numbers to ascertain that something unexpected did not happen,
> so should be relatively lightweight....
> 
> thoughts/comments?
> -- ramki
> 
> On Mon, Mar 12, 2012 at 12:40 PM, Staffan Larsen <staffan.larsen at oracle.com> wrote:
> Maybe a little off-topic, but there are plans to revise JVM logging as a whole. As part of this, it is planned that logging can be turned on and off at runtime. A JEP is in progress.
> 
> Thanks,
> /Staffan
> 
> 
> On 12 mar 2012, at 20:26, Srinivas Ramakrishna wrote:
> 
>> 
>> Hi all --
>> 
>> What's the plan for:
>> 
>> 6950384 We should make some / all GC logging parameters manageable
>> 
>> Is this on the cards for the near-future?
>> 
>> I'd be very interested to see this happen because it really improves the JVM/GC
>> serviceability/obsevability story (at least from a low-level perspective).
>> 
>> thanks for any info!
>> -- ramki
>> 
>> PS: Aside: the CR is specific to hotspot/gc -- are there corresponding plans for
>> flags from any of the other components within the JVM besides GC?
>> (My current interest is only in some of the GC logging flags, so this is
>> really more a curiosity wrt other parts of the JVM, rather than an explicit
>> interest at this time in those other flags.)
> 
> 

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