RFR (XS) 8215221: Serial GC misreports young GC time
Man Cao
manc at google.com
Wed Mar 6 18:30:21 UTC 2019
Thanks, Aleksey. The new webrev looks good.
-Man
On Wed, Mar 6, 2019 at 4:40 AM Aleksey Shipilev <shade at redhat.com> wrote:
> Hi Man,
>
> Thanks for taking a look. New webrev:
> http://cr.openjdk.java.net/~shade/8215221/webrev.03/
>
> Still passes hotspot tier1, eyeballing Dacapo logs, jdk-submit is running.
>
>
> On 2/22/19 4:43 AM, Man Cao wrote:
> > I found the following could fix the problem (yes, it's ugly, but I
> couldn't find cleaner way that
> > works in all cases):
> >
> > if (!do_young_collection) {
> > gc_prologue(complete);
> > increment_total_collections(complete);
> > }
> > if (!complete) {
> > increment_total_full_collections();
> > }
>
> I see, dang. Rewritten like this:
>
> if (!do_young_collection) {
> gc_prologue(complete);
> increment_total_collections(complete);
> }
>
> // Accounting quirk: total full collections would be incremented when
> "complete"
> // is set, by calling increment_total_collections above. However, we
> also need to
> // account Full collections that had "complete" unset.
> if (!complete) {
> increment_total_full_collections();
> }
>
> > I also found that CollectedHeap._total_collections seems wrong with or
> without this change, for
> > SerialGC and CMS. It is smaller than the actual number of collections
> according to the GC ID.
> > Reproduction recipe is the same as above.
> Yeah, that minor thing needs to be fixed too, in a separate change.
>
> -Aleksey
>
>
>
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