Ivan, Salikh, good idea and thanks for the info. We'd want to apply the work into Harmony GC.
Thanks, xiaofeng On 8/25/06, Salikh Zakirov <[EMAIL PROTECTED]> wrote:
Ivan Volosyuk wrote: > Yes, I have experimented with per-slot verification of write barrier. > > The idea was the following: each word in java heap has external mirror > record. After garbage collection all mirror records are synchronized > with the heap. Each write barrier updates mirror record with > corresponding data. Before next garbage collection there is a trace > for all reachable objects in heap which validates that each slot > contains the same data as the mirror. > > The idea is quite simple. Even that, it helped my find number of > places in VM code which have updated slots in heap without call to > write barrier. The results of the work are in HARMONY-504. > > The scheme has one impotant limitation. When several threads write to > single slot, this verifier may report false-positive result of missing > write barrier. But, I didn't see such situtations in any workloads I > have tested it with. The infrastructure based on the same idea, but independent of GC implementation is submitted as HARMONY-881. It provides patch for the VM, which incorporates the heap mirroring framework for write barrier verification into the VM core, and can work with any garbage collector. --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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