RFR(S): 8025227: Add -XX: flag to print code cache sweeper statistics
albert.noll at oracle.com
Sat Sep 28 04:10:33 PDT 2013
On 28.09.2013 00:40, Christian Thalinger wrote:
> I've already pointed this out to Albert but before we can accept your
> contributions you need to sign the OCA. See:
> On Sep 27, 2013, at 7:39 AM, Tobias Hartmann <tobi.hartmann at gmail.com
> <mailto:tobi.hartmann at gmail.com>> 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:
>> Thanks again for your review.
>> 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:
>> 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,
>> On 9/25/13 12:20 AM, Tobias Hartmann wrote:
>> Please review the following small patch.
>> 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,
>> By the way, I'm Tobias Hartmann, a student from
>> Switzerland currently
>> working on my Master Thesis "Code Cache Optimizations for
>> Compiled Languages" on supervision of Albert Noll.
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