JEP 173: Remove Rarely-Used Combinations of Garbage Collectors
bengt.rutisson at oracle.com
Thu Dec 6 05:23:10 PST 2012
Hi Kirk and Ramki,
On 12/6/12 12:05 AM, Srinivas Ramakrishna wrote:
> I am thinking that if we have a "test case" or publicly available
> application that can serve as a "witness" to this, it would
> allow us to learn a few useful things on how regular CMS might do
> better for such apps, and understand the basis of
> this difference. (Unless you have already analysed it and can share
> your summary of it.)
Yes, I totally agree with this. If there are cases where i-CMS is better
than regular CMS we need to understand why and should try to get CMS to
perform as well (or better). This is a much more appealing solution to
me than to keep the extra complexity that i-CMS introduces.
Kirk, if you have log files of runs with CMS and i-CMS it would be great
if you can pass them along. I would be very interested in analyzing why
i-CMS would preform better than CMS.
> -- ramki
> On Wed, Dec 5, 2012 at 3:01 PM, Srinivas Ramakrishna
> <ysr1729 at gmail.com <mailto:ysr1729 at gmail.com>> wrote:
> Hi Kirk --
> On Wed, Dec 5, 2012 at 2:48 PM, Kirk Pepperdine <kirk at kodewerk.com
> <mailto:kirk at kodewerk.com>> wrote:
> Hi all,
> The JEP's are coming in fast and furious. There is a customer
> use case for iCMS.. it's used by low latency applications...
> and quite successfully in fact. iCMS manages large heaps much
> better than CMS does which translates into more manageable
> pause times... I've got logs from a number of customers that
> rely on iCMS.
> This is very interesting indeed (and something i had vaguely heard
> a few years ago from the general grapevine, although never
> actually understood
> why it must be so). Could you go a bit deeper on why this is so?
> What exactly is it about doing a "slow, spread-out, incremental
> CMS collection"
> that makes it work better than bang-bang vanilla CMS in large
> multi-core, server environments? Perhaps the insights from that
> might translate into
> something useful for vanilla CMS?
> Your experience does indicate that we must proceed with some
> caution here before we deprecate iCMS, given it might still have
> some useful life
> (notwithstanding my own instincts to the contrary -- in server
> environments -- expressed in an earlier email before I had seen
> -- ramki
> On 2012-12-05, at 11:10 PM, mark.reinhold at oracle.com
> <mailto:mark.reinhold at oracle.com> wrote:
> > Posted: http://openjdk.java.net/jeps/173
> > - Mark
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