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

[Chris Plummer]

Agreed. Looks good. (I'm not an official reviewer)

Chris

On 9/27/13 9:17 AM, Vladimir Kozlov wrote:
> 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.
>>
>>
>>
>>