RFR(S): 8025227: Add -XX: flag to print code cache sweeper statistics

Vladimir Kozlov vladimir.kozlov at oracle.com
Thu Sep 26 15:09:55 PDT 2013

I agree with Chris, we are collecting those counters anyway. I also like 
Chris's idea about collecting freed sizes. Note, some counters will be 
removed by 8020151 changes:



On 9/26/13 2:13 PM, Chris Plummer wrote:
> Hi Tobias,
> The one comment I would have is that the statistics you produce are all
> timing related, but the option name implies you would get a bit more
> than this. For example, maybe something like a count of the number of
> methods flushed (and maybe total size). So I would suggest either rename
> to PrintMethodFlushingTimingStatistics (and also rename the print
> method), or add some other useful statistics to the output. Probably all
> the counters located below the " Stat counters" comment are good candidates.
> best regards,
> Chris
> On 9/25/13 12:20 AM, Tobias Hartmann wrote:
>> Hi,
>> Please review the following small patch.
>> bug:�https://bugs.openjdk.java.net/browse/JDK-8025277
>> webrev:�http://cr.openjdk.java.net/~anoll/8025277/webrev.00/
>> <http://cr.openjdk.java.net/%7Eanoll/8025277/webrev.00/>
>> I added the diagnostic VM option�PrintMethodFlushingStatistics to
>> print statistics about the NMethodSweeper (sweep times) on exit. This
>> is useful to determine performance bottlenecks of applications that
>> heavily compile code (e.g. nashorn).
>> Thanks in advance!
>> Best regards,
>> Tobias
>> By the way, I'm Tobias Hartmann, a student from Switzerland currently
>> working on my Master Thesis "Code Cache Optimizations for Dynamically
>> Compiled Languages" on supervision of Albert Noll.

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