Heads up: Deprecating the CMS foreground mode

[Bengt Rutisson]

Hi Kris,

On 2013-10-26 18:40, Krystal Mok wrote:
> Hi guys,
>
> I've actually seen quite a few cases where people grep'd globals.hpp, 
> found the flag CMSFullGCsBeforeCompaction but not knowing what it 
> really is, and suffer from old gen fragmentation problems when they 
> set the flag to a value greater than zero. It's more like a trap than 
> a tool in these cases. I'll be glad when this flag is gone ;-)

Good point. Thanks!

Bengt

>
> Thanks,
> Kris
>
>
> On Sat, Oct 26, 2013 at 1:57 AM, Kirk Pepperdine <kirk at kodewerk.com 
> <mailto:kirk at kodewerk.com>> wrote:
>
>     Hi Bengt,
>
>     Thank you very much for this heads up. All I can say is that I
>     don't know anyone using the foreground collector, I don't know of
>     anyone using the flags needed to turn on the foreground collector
>     and I don't recall seeing any evidence of the foreground collector
>     in any of the logs that I've looked at.
>
>     So, unlike iCMS, I'm not about to add any resistance to the
>     decision to deprecate.
>
>     Regards,
>     Kirk
>
>     On 2013-10-24, at 2:48 PM, Bengt Rutisson
>     <bengt.rutisson at oracle.com <mailto:bengt.rutisson at oracle.com>> wrote:
>
>     >
>     > Hi all,
>     >
>     > Just a heads up for anyone using the CMS foreground collector.
>     >
>     > I just sent out a review request to this list that proposes a
>     change to print warning messages for the flags that enable the CMS
>     foreground collector. The review request is titled "JDK-8027132:
>     Print deprecation warning message for the flags controlling the
>     CMS foreground collector" and it would be good if any discussion
>     can be handled in that email thread.
>     >
>     > We don't know of anyone using the foreground collector, so I
>     thought I'd send out an extra email out to draw some attention to
>     the review request if there is anybody using it.
>     >
>     > Just to be clear. The change proposed now only prints warning
>     messages for some flags. Everything will keep working as before.
>     This is just to communicate that the foreground collector has been
>     deprecated. Hopefully we will follow this up with a change to
>     actually remove the support for the foreground collector for one
>     of the future major releases.
>     >
>     > Thanks,
>     > Bengt
>
>

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