RFR 8151706: Update VarHandle implementation to use @Stable arrays
Hi, Please review: http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/we... <http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/webrev/> Now that @Stable arrays are supported by C1 (thanks Vladimir!) we can switch from the explicit use of MemberName fields in VarForm to a @Stable MemberName[] array. I also took the opportunity to simplify the linking from a VarHandle impl to MemberName[] array, now that the implementation has settled down. This will reduce initialization costs and memory churn. I held off making further improvements for now. For example, VarForm can probably go away (also removing the dependency on ClassValue). A VarHandle instance can directly hold a MemberName[] array whose source reference is statically held on the associated VarHandle implementation. It should also be possible to lazily create MemberName instances as required, rather than aggressively doing so, which may further reduce initialization costs and memory usage in common cases. Paul.
Hi Paul, note this is a lower-case review. Having looked at 8151705, thumbs up for this one as well - they go hand in hand and looking at one of them only doesn't feel right. :-) Best, Michael
Am 08.04.2016 um 11:56 schrieb Paul Sandoz <paul.sandoz@oracle.com>:
Hi,
Please review:
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/we... <http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/webrev/>
Now that @Stable arrays are supported by C1 (thanks Vladimir!) we can switch from the explicit use of MemberName fields in VarForm to a @Stable MemberName[] array.
I also took the opportunity to simplify the linking from a VarHandle impl to MemberName[] array, now that the implementation has settled down. This will reduce initialization costs and memory churn.
I held off making further improvements for now. For example, VarForm can probably go away (also removing the dependency on ClassValue). A VarHandle instance can directly hold a MemberName[] array whose source reference is statically held on the associated VarHandle implementation. It should also be possible to lazily create MemberName instances as required, rather than aggressively doing so, which may further reduce initialization costs and memory usage in common cases.
Paul.
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On 8 Apr 2016, at 16:11, Michael Haupt <michael.haupt@oracle.com> wrote:
Hi Paul,
note this is a lower-case review. Having looked at 8151705, thumbs up for this one as well - they go hand in hand and looking at one of them only doesn't feel right. :-)
Thanks. I got ‘em swapped the wrong way around. I am gonna re-base this one and push, otherwise it will be blocked waiting on the CCC of 8151705.
On 8 Apr 2016, at 16:23, Aleksey Shipilev <aleksey.shipilev@oracle.com> wrote:
On 04/08/2016 12:56 PM, Paul Sandoz wrote:
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/we... <http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/webrev/>
Now that @Stable arrays are supported by C1 (thanks Vladimir!) we can switch from the explicit use of MemberName fields in VarForm to a @Stable MemberName[] array.
Yes, glad to see that abomination gone.
Indeed!
I've checked C1 and C2 performance against our battery of VarHandle microbenchmarks, and there were no regressions. So, +1.
Thanks, Paul.
Looks good /Claes On 2016-04-11 12:55, Paul Sandoz wrote:
On 8 Apr 2016, at 16:11, Michael Haupt <michael.haupt@oracle.com> wrote:
Hi Paul,
note this is a lower-case review. Having looked at 8151705, thumbs up for this one as well - they go hand in hand and looking at one of them only doesn't feel right. :-)
Thanks. I got ‘em swapped the wrong way around. I am gonna re-base this one and push, otherwise it will be blocked waiting on the CCC of 8151705.
On 8 Apr 2016, at 16:23, Aleksey Shipilev <aleksey.shipilev@oracle.com> wrote:
On 04/08/2016 12:56 PM, Paul Sandoz wrote:
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/we... <http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/webrev/>
Now that @Stable arrays are supported by C1 (thanks Vladimir!) we can switch from the explicit use of MemberName fields in VarForm to a @Stable MemberName[] array. Yes, glad to see that abomination gone.
Indeed!
I've checked C1 and C2 performance against our battery of VarHandle microbenchmarks, and there were no regressions. So, +1. Thanks, Paul.
On 04/08/2016 12:56 PM, Paul Sandoz wrote:
http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/we... <http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151706-VH-form-table-stable/webrev/>
Now that @Stable arrays are supported by C1 (thanks Vladimir!) we can switch from the explicit use of MemberName fields in VarForm to a @Stable MemberName[] array.
Yes, glad to see that abomination gone. I've checked C1 and C2 performance against our battery of VarHandle microbenchmarks, and there were no regressions. So, +1. Thanks, -Aleksey
participants (4)
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Aleksey Shipilev
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Claes Redestad
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Michael Haupt
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Paul Sandoz