RFR (XS) 8238247: CTW runner should sweep nmethods more aggressively

[Igor Ignatyev]

Hi Aleksey,

the path looks good to me, but it effectively makes DeoptimizeAllClassesRate property useless. I wasn't able to find any recollection why this property and corresponding functionality was added, could you please either file an RFE to get rid off it or remove as part of this fix?

-- Igor  

> On Feb 6, 2020, at 2:50 AM, Aleksey Shipilev <shade at redhat.com> wrote:
> 
> RFE:
>  https://bugs.openjdk.java.net/browse/JDK-8238247
> 
> Candidate fix:
>  https://cr.openjdk.java.net/~shade/8238247/webrev.01/
> 
> Current CTW runner leaves the just-compiled nmethods behind. At some point the sweeper comes in and
> make them go away, stabilizing on some number of nmethods. However, that stabilization point is too
> far away for the throwaway compilations CTW runner does.
> 
> In the end, this leads to inflation of nmethod and dependencies population, which slows down the
> subsequent compiles and deopts. If you have a very large JAR file, it would take days to CTW. With
> this patch, it takes a few hours. applications/ctw/modules also improves quite nicely with it. See
> the comments in bug report for additional details.
> 
> Testing: adhoc CTW runs, make run-test applications/ctw/modules
> 
> -- 
> Thanks,
> -Aleksey
>