Continuous CMS Collections Followed By Concurrent Mode Failure

[Srinivas Ramakrishna]

On Tue, Jul 8, 2014 at 12:06 AM, Kirk Pepperdine <kirk at kodewerk.com> wrote:

> ...
> Ramki, should we file a bug for the ParNew (promotion failed) being
> corrupted by a CMS cycle?
>
>
Can you elaborate what precisely you meant by "corrupted (formatting)"
below?

Perhaps you want what seems to be a missing newline or something? You
should check with Jon or one of the HotSpot/GC folks on whether and how
easy it would be to fix, or otherwise modify your parser. (Kevlar suit
donned, for yr response ;-)

-- ramki

>
> That was actually my guess. There is only 1 perm record in the file and
> although it shows that perm is grossly over-sized (ok, there is only one
> record ;-)) all of the recovery comes from the CMF which suggests perm is
> involved. All of the other CMS cycles are clearly due to tenured never
> being below the initiating occupancy fraction. Even without a young
> collection the initial marks are constantly reporting an occupancy of
> >1920xxxK of 1929xxxK. Oddly enough the ParNew’s only once promoted enough
> to trip the concurrent mode failure and oddly enough each of the CMS cycles
> (without the intervening ParNew) seem to recover about 1xxK bytes per cycle.
>
> 2014-06-10T22:56:18.793-0700: 4999527.565: [GC [1 CMS-initial-mark:
> 1920286K(1926784K)] 2051254K(2080128K), 0.3388330 secs] [Times: user=0.33
> sys=0.00, real=0.33 secs]
> …...
> 2014-06-10T22:56:26.242-0700: 4999535.014:
> [GC2014-06-10T22:56:26.242-0700: 4999535.014:
> [ParNew2014-06-10T22:56:26.256-0700: 4999535.028:
> [CMS-concurrent-abortable-preclean: 1.948/3.114 secs] [Times: user=1.93
> sys=0.12, real=3.11 secs]
>  (promotion failed)
> Desired survivor size 8716288 bytes, new threshold 6 (max 6)
> - age   1:    1036320 bytes,    1036320 total
> - age   2:     825248 bytes,    1861568 total
> - age   3:     119024 bytes,    1980592 total
> - age   4:     113784 bytes,    2094376 total
> - age   5:     129024 bytes,    2223400 total
> - age   6:     154976 bytes,    2378376 total
> : 141769K->140729K(153344K), 0.3807730 secs]2014-06-10T22:56:26.623-0700:
> 4999535.395: [CMS
>  (concurrent mode failure): 1920816K->50773K(1926784K), 28.3938140 secs]
> 2062055K->50773K(2080128K), [CMS Perm : 48657K->41071K(262144K)],
> 28.7750370 secs] [Times: user=1.65 sys=0.03, real=28.78 secs]
> 2014-06-10T22:58:41.361-0700: 4999670.133:
> [GC2014-06-10T22:58:41.361-0700: 4999670.133: [ParNew
> Desired survivor size 8716288 bytes, new threshold 6 (max 6)
> - age   1:    1239232 bytes,    1239232 total
> : 136320K->2239K(153344K), 0.0223680 secs] 187093K->53012K(2080128K),
> 0.0226340 secs] [Times: user=0.05 sys=0.00, real=0.02 secs]
>
> Note the corrupted formatting of the ParNew (promotion failed).
>
>
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