What influences young generation pause times?

Tony Printezis tony.printezis at oracle.com
Tue Apr 20 07:04:32 PDT 2010


Matt,

For most applications, object copying is the predominant cost during 
young GCs. Basically, the more objects survive the collection and need 
to be copied, the higher the young GC times will be. Young GCs do not 
touch the dead objects in the young generation so the number of overall 
objects in the young generation will not really affect pause times, just 
the number of live ones.

There are other costs during young GCs, like scanning the application 
thread stacks, scanning the card table to find old-to-young references, 
etc. However, typically, those costs are very small compared to copying 
the live objects.

Hope this helps,

Tony

Matt Khan wrote:
>
> Hi
>
> My understanding is that young gen pause times are related to the size 
> of the set of live objects but what does this really mean? for example 
> does it mean number of objects in the live set? total size [of them]?
>
> and what other factors influence the young gen pause time?
>
> Cheers
> Matt
>
> Matt Khan
> --------------------------------------------------
> GFFX Auto Trading
> Deutsche Bank, London
>
>
> ---
>
> This e-mail may contain confidential and/or privileged information. If 
> you are not the intended recipient (or have received this e-mail in 
> error) please notify the sender immediately and delete this e-mail. 
> Any unauthorized copying, disclosure or distribution of the material 
> in this e-mail is strictly forbidden.
>
> Please refer to http://www.db.com/en/content/eu_disclosures.htm for 
> additional EU corporate and regulatory disclosures.
> ------------------------------------------------------------------------
>
> _______________________________________________
> hotspot-gc-use mailing list
> hotspot-gc-use at openjdk.java.net
> http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
>   
_______________________________________________
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