Request for review (XS): 8003822: Deprecate the incremental mode of CMS

Srinivas Ramakrishna ysr1729 at gmail.com
Fri Jan 4 23:08:30 UTC 2013


On Wed, Dec 19, 2012 at 12:46 PM, Joel Buckley <joel.buckley at oracle.com>wrote:

> Hey Bengt,
>
> Code review looks simple enough.
>
> One nit on naming consistency:
> Should "CMSIncrementalMode" be "UseCMSIncrementalGC"
> to be consistent with other flags?
>

Historical name, probably not worth renaming especially since that mode is
being deprecated now.


> A couple more general questions:
>
> What GC combinations are non-deprecated and what are their
> intended use cases?
>
> For example, what GC combinations are intended for the following?:
> * 4-100GB Heap (e.g. 64bit);  High Priority: 200ms max pause due to GC;
> Env: >50% Heap long lived (>12hour)
> * 4-100GB Heap (e.g. 64bit);  High Priority: 500ms max pause due to GC;
> Env: ~40% Heap short lived (<1minute) & ~40% Heap long lived (>12hour)
> * 1-3.5GB Heap (e.g. 32bit); High Priority: 200ms max pause due to GC;
> Env: ~90% Heap short lived (<1minute)
> * 100-1024MB Heap (e.g. 32bit/embedded); High Priority: 500ms max pause
> due to GC; Env: varying short/long lived data profiles over time
>

guesstimate: Probably CMS and G1 for all these cases except for embedded,
where serial or parallel would probably work. #2 and #3 could probably be
tuned for parallel old.

-- ramki


>
> Thanks,
> Joel.
>
> Date: Wed, 19 Dec 2012 13:40:18 +0100
> From: Bengt Rutisson <bengt.rutisson at oracle.com>
> Subject: Request for review (XS): 8003822: Deprecate the incremental
> mode of CMS
> To: hotspot-gc-dev at openjdk.java.net
> Message-ID: <50D1B5B2.4010709 at oracle.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>
>
> Hi all,
>
> Can I have a couple of reviews for this change to deprecate iCMS?
>
> http://cr.openjdk.java.net/~brutisso/8003822/webrev.00/
>
> This is part of the work for JEP 173:
>
> JEP 173: Retire Some Rarely-Used GC Combinations
> http://openjdk.java.net/jeps/173
>
> The webrev is based on the the earlier webrev that I sent out to
> deprecate the DefNew + CMS and ParNew + SerialOld GC combinations:
>
> http://cr.openjdk.java.net/~brutisso/8003820/webrev.00/
>
> Thanks,
> Bengt
>
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