RFR(L): 8074981 (Integer/FP scalar reduction optimization )
Vitaly Davidovich
vitalyd at gmail.com
Wed Apr 8 19:57:46 UTC 2015
Sounds good to me, I'll take what I can get :)
Thanks
On Wed, Apr 8, 2015 at 3:41 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com>
wrote:
> Note, that if we backport loop reduction vectorization, we backport only
> 8074981 changes as they are:
>
> http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/6fff5df5f3d2
>
> There will be no support for MulVL in it which requires avx512.
>
> Regards,
> Vladimir
>
> On 4/7/15 12:12 PM, Vitaly Davidovich wrote:
>
>> Oh, the motivation is there! :) However, it's not always a quick process
>> even if everyone's motivated as there may be
>> changes of consequence. As a small example, java 8 virtual memory charge
>> is significantly higher than java 7 due to
>> metaspace vs permgen differences. In some cases, this now requires
>> tweaking java 8 settings in order to keep things
>> running smoothly. With a big enough codebase, such migrations are never
>> as quick as one would hope.
>>
>> At any rate, yes, I meant loop reduction vectorization. It seems like a
>> fairly self-contained change which should be
>> relatively painless to backport, hence my inquiry.
>>
>> On Tue, Apr 7, 2015 at 3:04 PM, Vladimir Kozlov <
>> vladimir.kozlov at oracle.com <mailto:vladimir.kozlov at oracle.com>> wrote:
>>
>> We want to motivate people to migrate to new releases :)
>> If you mean loop reduction vectorization we can consider it after it
>> is tested for some time in jdk9.
>>
>> Vladimir
>>
>> On 4/7/15 11:55 AM, Vitaly Davidovich wrote:
>>
>> Ok, thanks. That makes sense for avx512 support, but I think
>> having Michael's changes from this thread sooner
>> would be
>> nice as it's quite likely that users are already running java 8
>> on hardware where this may have benefit. Java 9 is
>> still ways away, and even when it's released, the migration
>> process is not always quick (depending on the nature of
>> major changes). But, if backporting it is messy, it's probably
>> not worth it.
>>
>> On Tue, Apr 7, 2015 at 2:38 PM, Vladimir Kozlov <
>> vladimir.kozlov at oracle.com <mailto:vladimir.kozlov at oracle.com>
>> <mailto:vladimir.kozlov at __oracle.com <mailto:vladimir.kozlov@
>> oracle.com>>> wrote:
>>
>> Currently it is only jdk9. There are no plans to backport to
>> 8u.
>> The thinking is that we will get jdk9 released when this
>> hardware will be widely available.
>>
>> Regards,
>> Vladimir
>>
>> On 4/7/15 11:30 AM, Vitaly Davidovich wrote:
>>
>> Hi Michael/Vladimir,
>>
>> Out of curiosity, is this change and the out-for-review
>> avx512 one going to be (or planned on being)
>> backported
>> to java 8?
>>
>> Thanks
>>
>> On Tue, Apr 7, 2015 at 2:07 PM, Berg, Michael C <
>> michael.c.berg at intel.com
>> <mailto:michael.c.berg at intel.com> <mailto:michael.c.berg at intel.__com
>> <mailto:michael.c.berg at intel.com>>
>> <mailto:michael.c.berg at intel. <mailto:
>> michael.c.berg at intel.>____com <mailto:michael.c.berg at intel.__com
>> <mailto:michael.c.berg at intel.com>>>> wrote:
>>
>> Please ignore this one its already checked in…____
>>
>> __ __
>>
>> *From:* hotspot-compiler-dev [mailto:
>> hotspot-compiler-dev-____bounces at openjdk.java.net
>> <mailto:hotspot-compiler-dev-__bounces at openjdk.java.net>
>> <mailto:hotspot-compiler-dev-__bounces at openjdk.java.net
>> <mailto:hotspot-compiler-dev-bounces at openjdk.java.net>>
>> <mailto:hotspot-compiler-dev-_
>> ___bounces at openjdk.java.net
>> <mailto:hotspot-compiler-dev-__bounces at openjdk.java.net>
>> <mailto:hotspot-compiler-dev-__bounces at openjdk.java.net
>> <mailto:hotspot-compiler-dev-bounces at openjdk.java.net>>>] *On
>> Behalf Of *Berg, Michael C
>> *Sent:* Monday, March 16, 2015 2:18 PM
>> *To:* hotspot-compiler-dev at openjdk.____java.net <
>> http://java.net>
>> <mailto:hotspot-compiler-dev at __openjdk.java.net <mailto:
>> hotspot-compiler-dev at openjdk.java.net>>
>> <mailto:hotspot-compiler-dev@ <mailto:
>> hotspot-compiler-dev@>____openjdk.java.net
>> <http://openjdk.java.net> <mailto:hotspot-compiler-dev at __
>> openjdk.java.net
>> <mailto:hotspot-compiler-dev at openjdk.java.net>>>
>> *Subject:* RFR(L): 8074981 (Integer/FP scalar
>> reduction optimization )____
>>
>> __ __
>>
>> Hi All,____
>>
>> __ __
>>
>> We would like to contribute the Integer/FP scalar
>> reduction optimization from Intel.____
>>
>> The contribution is referenced as Bug ID 8074981 as
>> a performance enhancement. ____
>>
>> __ __
>>
>> Please review this patch:____
>>
>> Bug-id: https://bugs.openjdk.java.net/
>> ____browse/JDK-8074981
>> <https://bugs.openjdk.java.net/__browse/JDK-8074981>
>> <https://bugs.openjdk.java.__net/browse/JDK-8074981 <
>> https://bugs.openjdk.java.net/browse/JDK-8074981>>
>> ____
>>
>> webrev: https://bugs.openjdk.java.net/
>> ____secure/attachment/26101/____webrev.zip
>> <https://bugs.openjdk.java.net/__secure/attachment/26101/
>> __webrev.zip>
>> <https://bugs.openjdk.java.__
>> net/secure/attachment/26101/__webrev.zip
>> <https://bugs.openjdk.java.net/secure/attachment/26101/webrev.zip>>
>> ____
>>
>> __ __
>>
>> The optimization achieves as much as 2.3x on
>> integer reductions and supports float and double
>> precision
>> optimizations____
>>
>> which also have significant optimization uplift an
>> obey strict fp constraints.____
>>
>> __ __
>>
>> Nils Eliasson has offered to sponsor this patch.____
>>
>> __ __
>>
>> Thanks,____
>>
>> __ __
>>
>> -Michael____
>>
>> __ __
>>
>>
>>
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20150408/94d2caf7/attachment-0001.html>
More information about the hotspot-compiler-dev
mailing list