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

[Vladimir Kozlov]

Looks good to me.

Thanks,
Vladimir

On 9/27/13 7:39 AM, Tobias Hartmann wrote:
> Chris, Vladimir, thank you for your reviews.
> I followed your suggestions and added other useful statistics. The output now looks like this:
>
> Method flushing statistics:
>    Total sweep time: 152.649ms
>    Peak sweep time: 15.979ms
>    Peak sweep fraction time: 3.209ms
>    Total number of stack traversals: 25
>    Total number of flushed methods: 1320
>    Total size of flushed methods: 7188Kb
>
> I did not include the other values, because as Vladimir already said, they are removed by 8020151.
>
> Here is the new webrev:
> http://cr.openjdk.java.net/~anoll/8025277/webrev.01/
>
> Thanks again for your review.
>
> Regards,
> Tobias
>
>
>
>
> 2013/9/27 Vladimir Kozlov <vladimir.kozlov at oracle.com <mailto:vladimir.kozlov at oracle.com>>
>
>     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:
>
>     http://cr.openjdk.java.net/~__anoll/8020151/webrev.03/ <http://cr.openjdk.java.net/~anoll/8020151/webrev.03/>
>
>     Thanks,
>     Vladimir
>
>
>     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 PrintMethodFlushingTimingStati__stics (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 <https://bugs.openjdk.java.net/browse/JDK-8025277>
>             webrev:�http://cr.openjdk.__java.net/~anoll/8025277/__webrev.00/
>             <http://cr.openjdk.java.net/~anoll/8025277/webrev.00/>
>             <http://cr.openjdk.java.net/%__7Eanoll/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.
>
>
>
>