RRF: JEP-271: Unified GC Logging

Bengt Rutisson bengt.rutisson at oracle.com
Mon Nov 23 08:43:47 UTC 2015


Hi Per,

Thanks for looking at this!

On 2015-11-23 09:51, Per Liden wrote:
> Hi Bengt,
>
> On 2015-11-19 16:29, Bengt Rutisson wrote:
>>
>> Hi everyone,
>>
>> After three pre-reviews it is time for the fist official review request
>> for JEP-271 Unified GC Logging.
>>
>> http://openjdk.java.net/jeps/271
>>
>> Most code changes are in the hotspot code:
>> http://cr.openjdk.java.net/~brutisso/JEP-271/review.00/webrev.00/
>
> This is not a complete review, just a few things I noticed while 
> browsing the webrev.
>
> ----------------------------------------------
> /src/share/vm/gc/g1/g1StringDedupQueue.cpp
>
>  157   log_trace(gc, stringdedup)(
>  158     "   [Queue]\n"
>  159     "      [Dropped: " UINTX_FORMAT "]", _queue->_dropped);
>
> Multi-line loging.
>
> ----------------------------------------------
> src/share/vm/gc/g1/g1StringDedupTable.cpp
>
>  573   log_trace(gc, stringdedup)(
>  574     "   [Table]\n"
>  575     "      [Memory Usage: " G1_STRDEDUP_BYTES_FORMAT_NS "]\n"
>  576     "      [Size: " SIZE_FORMAT ", Min: " SIZE_FORMAT ", Max: " 
> SIZE_FORMAT "]\n"
>  577     "      [Entries: " UINTX_FORMAT ", Load: " 
> G1_STRDEDUP_PERCENT_FORMAT_NS ", Cached: " UINTX_FORMAT ", Added: " 
> UINTX_FORMAT ", Removed: " UINTX_FORMAT "]\n"
>  578     "      [Resize Count: " UINTX_FORMAT ", Shrink Threshold: " 
> UINTX_FORMAT "(" G1_STRDEDUP_PERCENT_FORMAT_NS "), Grow Threshold: " 
> UINTX_FORMAT "(" G1_STRDEDUP_PERCENT_FORMAT_NS ")]\n"
>  579     "      [Rehash Count: " UINTX_FORMAT ", Rehash Threshold: " 
> UINTX_FORMAT ", Hash Seed: 0x%x]\n"
>  580     "      [Age Threshold: " UINTX_FORMAT "]",
>
> Multi-line logging.
>
> ----------------------------------------------

Good catch. Will fix.

> src/share/vm/gc/g1/g1StringDedup*.cpp
>
> In general, I think the string dedup logging currently done with 
> log_trace() should be log_debug() instead.

Yes, that makes sense. Will change that.

Bengt


>
> cheers,
> /Per
>
>>
>> Some tests in the JDK repo have been updated:
>> http://cr.openjdk.java.net/~brutisso/JEP-271/review.00/jdk-webrev.00/
>>
>> As with the pre-reviews I have put togther some examples of what the new
>> logging looks like:
>> http://cr.openjdk.java.net/~brutisso/JEP-271/review.00/compare.html
>>
>> The intent is that this should cover the bulk of the logging changes.
>> There will most definitely be some follow up changes where we fix
>> details in the log messages etc.
>>
>> Among many other old logging flags this changeset removes the two flags
>> PringGC and PrintGCDetails. These two will be added back with a follow
>> up changeset, but when they are added back they will be marked as
>> deprecated.
>>
>> The reason for first removing them and then adding them back is to get
>> testing without these flags. That way we will know that we clean out all
>> usages of these flags from our testing.
>>
>> Thanks,
>> Bengt



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