Reporting large Java heap allocations (was Re: RMI Activity Threads Lock GC o/p)

Michael Finocchiaro michael.finocchiaro at gmail.com
Fri Apr 4 12:57:14 PDT 2008


I am talking about a single allocation exceeding some preset limit (see the
URL in the original post as to how IBM/s JVM does it).
Fino

On Fri, Apr 4, 2008 at 9:50 PM, Y Srinivas Ramakrishna <
Y.S.Ramakrishna at sun.com> wrote:

> By the way, i am assuming you mean a single large allocation here,
> not the total heap occupancy exceeding some specified threahold.
> (For the latter, recall that the JVM Management & Monitoring JMX API's do
> allow for
> some form of reportage when the heap occupancy exceeds
> a certain threshold, but I am guessing you do not have that in mind here).
>
> -- ramki
>
> ----- Original Message -----
> From: Y Srinivas Ramakrishna <Y.S.Ramakrishna at Sun.COM>
> Date: Friday, April 4, 2008 12:45 pm
> Subject: Re: Reporting large Java heap allocations (was Re: RMI Activity
> Threads Lock GC o/p)
> To: Michael Finocchiaro <michael.finocchiaro at gmail.com>
> Cc: Keith Holdaway <Keith.Holdaway at sas.com>,
> hotspot--runtime-dev at openjdk.java.net, "hotspot-gc-use at openjdk.java.net" <
> hotspot-gc-use at openjdk.java.net>
>
>
> > Sorry, corrected the runtime list address below. Apologies for the
> > resulting clutter.
> >
> > -- ramki
> >
> > ----- Original Message -----
> > From: Y Srinivas Ramakrishna <Y.S.Ramakrishna at Sun.COM>
> > Date: Friday, April 4, 2008 12:40 pm
> > Subject: Reporting large Java heap allocations (was Re: RMI Activity
> > Threads Lock GC o/p)
> > To: Michael Finocchiaro <michael.finocchiaro at gmail.com>
> > Cc: Keith Holdaway <Keith.Holdaway at sas.com>,
> > "hotspot-gc-use at openjdk.java.net" <hotspot-gc-use at openjdk.java.net>,
> hotspot-runtime-dev at openjdk.java.net
> >
> >
> > > Hi Fino --
> > >
> > > > Yes, there is an environment variable on AIX called
> > > > ALLOCATION_THRESHOLD=<size in bytes> that when set will have the
> > JVM
> > >
> > > > send on
> > > > error to stdout (or stderr not sure) when an allocation greater
> > than
> > > <size
> > > > in bytes> occurs. This could be useful, well at least for us, when
> > dealing
> > > > with code that sends back way too much data. By the heap blowing
> > up,
> > > I
> > > > mean
> > > > a sudden huge jump in memory consumption from which the heap may
> > > have
> > > > a real
> > > > hard time recovering if at all. Even better would be a flag that
> > > threw
> > > > a
> > > > stack trace when that allocation occurs.
> > >
> > > ...
> > >
> > > I don't think there is a jvm (or env option) w/Hotspot that would do
> > that
> > > (but i may be wrong).
> > >
> > > However, I also wonder whether (with appropriate caveats, see below,
> >
> > > on appropriate
> > > platforms) one might be able to elicit (an approximation to) that
> > data
> > > (at
> > > sufficiently large values of <size_in_bytes>) by leveraging dtrace;
> > someone
> > > on hotspot-runtime-dev at o.j.n might be able to help, so i have
> cross-posted
> > > to that list.
> > >
> > > -- ramki
> > >
> > _______________________________________________
> > hotspot-gc-use mailing list
> > hotspot-gc-use at openjdk.java.net
> > http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
>



-- 
Michael Finocchiaro
michael.finocchiaro at gmail.com
Mobile Telephone: +33 6 67 90 64 39
MSN: le_fino at hotmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20080404/e07d46eb/attachment.html 
-------------- next part --------------
_______________________________________________
hotspot-gc-use mailing list
hotspot-gc-use at openjdk.java.net
http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use


More information about the hotspot-gc-dev mailing list