RFR(XS) 8059780: SPECjvm2008-MPEG performance regressions on x64 platforms
vladimir.kozlov at oracle.com
Sat Nov 1 00:58:39 UTC 2014
I forgot to say that lcm.cpp changes were small part of 8052081 changes.
The rest of changes will stay.
On 10/31/14 5:55 PM, Vladimir Kozlov wrote:
> We found performance regression (3-5%) on x64 after changes 8052081 
> were pushed. It is caused by changes in lcm.cpp. Those changes were done
> because Atom is in-order cpu and some benchmarks on Atom showed benefit
> from these changes.
> But Atom is not our core platform and the regression is big.
> Backout changes made in lcm.cpp in jdk9 and 8u40 (8052081 was backported
> to 8u40).
> We have RFEs to improve block's instructions order which may help both
> Tested with SPECjvm2008-mpegaudio.
>  https://bugs.openjdk.java.net/browse/JDK-8052081
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