RFR(S): x86:8190934: Regressions on Haswell Xeon due to JDK-8178811

[Deshpande, Vivek R]

Thanks Claes for conforming!
Also thanks to Nils for starting the testing right away.

Regards,
Vivek
From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-bounces at openjdk.java.net] On Behalf Of Claes Redestad
Sent: Thursday, December 14, 2017 5:50 AM
To: hotspot-compiler-dev at openjdk.java.net
Subject: Re: RFR(S): x86:8190934: Regressions on Haswell Xeon due to JDK-8178811


Hi,

not a review, but I've verified that this resolves a number of regressions we've seen in various microbenchmarks.

Thanks!

/Claes

On 2017-12-14 13:00, Nils Eliasson wrote:

Hi Vivek,

I have started regular testing of your patch. Hopefully the testing will be complete when Vladimir comes online.

Regards,

Nils

On 2017-12-14 08:22, Deshpande, Vivek R wrote:
Hi Vladimir

I have a fix for the slowdown observed on haswell due to jdk-8178811.
The solution selectively generates vzeroupper when AVX2/ AVX512 instructions have been executed and before the transition to SSE code.
I tested this fix with the test case given with bug and SPECjbb2015.
Could you please review and sponsor the patch?
Webrev:
http://cr.openjdk.java.net/~vdeshpande/8190934/webrev.00/<http://cr.openjdk.java.net/%7Evdeshpande/8190934/webrev.00/>
I have also updated the bug: https://bugs.openjdk.java.net/browse/JDK-8190934

Regards,
Vivek


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