RFR: 8251322: Improve BitMap::iterate

Thomas Schatzl thomas.schatzl at oracle.com
Mon Aug 10 07:41:09 UTC 2020


Hi,

On 09.08.20 09:44, Kim Barrett wrote:
> Please review this improvement to BitMap::iterate.  The code is both
> simplified and made more performant by using get_next_one_bit to scan
> the bitmap.  Making it inline may allow the compiler to devirtualize
> and possibly inline the closure invocation.  These changes result in
> some configurations executing ~1M fewer instructions during startup.
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8251322
> 
> Webrev:
> https://cr.openjdk.java.net/~kbarrett/8251322/open.00/
> 
> Testing:
> mach5 tier1-3.
> Used Linux-x64 perf on java -version to examine startup impact.
> 
> 

lgtm.

Thanks,
   Thomas


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