Anything in hs25-b47 or b47 that would cause a significant performance regression?

[Alan Bateman]

On 12/09/2013 12:10, Alan Bateman wrote:
>
> This is a long shot but does anyone know of any performance 
> regressions that might have crept in recently, specifically in 
> jdk8-b105 or jdk8-b106 (hs25-b47 or hs25-b48).
>
> jdk8/tl was sync'ed up to jdk8-b106 (it had been at b104) last Friday 
> and since then several of us have noticed significant slowdowns 
> (20-30%) in the time is takes to run the jdk tests. The jdk tests run 
> in agent VM mode that should mostly eliminate startup for most of the 
> tests. As jdk8/tl is always ahead of jdk8/jdk8 with library changes 
> then it means that the only interesting changes that the sync up 
> brought in is the HotSpot changes.
>
> I don't think anyone of has had the time to attempt to bisect this yet 
> (or know if this is all or only some OS/arch) and this mail is just to 
> see whether it rings any bells with anyone.
>
> -Alan
>
Just to follow up on this, it seems to be due to large pages, most 
likely the changes in JDK-8007074. Running with -XX:-UseLargePages 
restores the performance, at least on Linux x64 (Ubuntu 12.04LTS).

-Alan.