RFR(L): 8077838: Recent developments for ppc.
goetz.lindenmaier at sap.com
Thu Apr 23 14:37:55 UTC 2015
Yes, the ldarx and stdcx are a pair. The store is only executed
if the memory didn't change since the load was done.
Else a condition is set.
The condition is used to repeat the sequence.
From: Vladimir Kozlov [mailto:vladimir.kozlov at oracle.com]
Sent: Donnerstag, 23. April 2015 16:24
To: Lindenmaier, Goetz; hotspot-dev at openjdk.java.net
Subject: Re: RFR(L): 8077838: Recent developments for ppc.
On 4/23/15 1:27 AM, Lindenmaier, Goetz wrote:
> Hi Vladimir,
> thanks for the review!
> These methods actually do an atomic update of a memory location, so the name
> really describes what is happening.
May be I need some PPC education. There are several instructions and branch. Is that some kind of transaction?
> I'll remove the change to interpreter_ppc.cpp and runtime_ppc.cpp.
> Best regards,
> -----Original Message-----
> From: hotspot-dev [mailto:hotspot-dev-bounces at openjdk.java.net] On Behalf Of Vladimir Kozlov
> Sent: Donnerstag, 23. April 2015 01:16
> To: hotspot-dev at openjdk.java.net
> Subject: Re: RFR(L): 8077838: Recent developments for ppc.
> Why call methods 'atomic': atomic_inc_ptr() and atomic_ori_int()?
> Do you really need to change runtime_ppc.cpp only to remove empty line?
> Looks fine otherwise.
> On 4/22/15 2:34 AM, Lindenmaier, Goetz wrote:
>> this change contains recent changes in the ppc directory mostly made by SAP.
>> It's a ppc-only change.
>> - Recognition of Power 8 processors (by Tiago Sturmer Daitx).
>> - Support for more new Power 8 instructions.
>> - Support for transactional memory. This is implemented but not yet tested
>> thoroughly due to limitiations of the OS support. Not enabled.
>> - java.lang.math.*Exact intrinsics
>> - Some C2 optimizations and fixes:
>> * Handling of flag registers. Some instructions would lead to uncompilable
>> methods due to not allocatable register patterns.
>> * Free some integer registers to use them for allocation. Handle compressed
>> oops base as constant.
>> * Unscaled class compression.
>> - Type profiling fixes.
>> Please review this change.
>> Best regards,
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