GC metrics you should care

  • gen0(s)     – young gen collection time, excluding gc_prologue & gc_epilogue.
  • gen0t(s)    – young gen collection time, including gc_prologue & gc_epilogue
  • gen0usr(s)  – young gen collection time in cpu user secs
  • gen0sys(s)  – young gen collection time in cpu sys secs
  • gen1i(s)    – train generation incremental collection
  • gen1t(s)    – old generation collection/full GC
  • cmsIM(s)    – CMS initial mark pause
  • cmsRM(s)    – CMS remark pause
  • cmsRS(s)    – CMS resize pause // rarely look. Probably we set OG at fixed size
  • GC(s)       – all stop-the-world GC pauses
  • cmsCM(s)    – CMS concurrent mark phase   // don’t care
  • cmsCP(s)    – CMS concurrent preclean phase // don’t care
  • cmsCS(s)    – CMS concurrent sweep phase // don’t care
  • cmsCR(s)    – CMS concurrent reset phase // don’t care
  • alloc(MB)   – object allocation in MB (approximate***)
  • promo(MB)   – object promotion in MB (approximate***)
  • used0(MB)   – young gen used memory size (before gc)
  • used1(MB)   – old gen used memory size (before gc)
  • used(MB)    – heap space used memory size (before gc) (excludes perm gen)
  • commit0(MB) – young gen committed memory size (after gc)
  • commit1(MB) – old gen committed memory size (after gc)
  • commit(MB)  – heap committed memory size (after gc) (excludes perm gen)
  • apptime(s)  – amount of time application threads were running
  • appstop(s) – amount of time application threads were stalled
  • safept(s)   – amount of time the VM spent at safepoints (app threads stopped)
Advertisements

Leave a comment

Filed under JVM

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s