very slow perm gen verification

Y. Srinivas Ramakrishna y.s.ramakrishna at
Thu May 12 18:49:55 UTC 2011

With the framework collectors there was a badness that
would cause O(n^2) in the size of the perm gen in the phase
that checks that clean cards do not have cross-generational
pointers. I fixed it a few weeks ago so it is now O(n) -- i can dig up the
CR if you can't find it. Are you seeing this with a specific
collector or all?

-- ramki

On 5/12/2011 10:33 AM, John Coomes wrote:
> John Coomes (John.Coomes at wrote:
>> When running some nsk tests, I saw several timeouts which appear to be
>> due to very slow verification of the perm gen (i.e., 10+ minutes to
>> verify a 64MB perm gen (par scavenge)), which is done as the jvm is
>> exiting.  Happens frequently, but not every time; and w/my changes as
>> well as w/jdk7-b141.
>> I vaguely recall some discussion of this a few months ago, but can't
>> find any record of it :-(.  Sound familiar to anyone?
> In case it's not obvious to some, the verification is done only in
> non-product builds.
> -John

More information about the hotspot-gc-dev mailing list