RRF: JEP-271: Unified GC Logging

Per Liden per.liden at oracle.com
Mon Nov 23 08:51:35 UTC 2015


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.

----------------------------------------------
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.

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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