JDK10/RFR(L): 8172231: SPARC ISA/CPU feature detection is broken/insufficient (on Solaris).

[Stefan Anzinger]

Hi Patric,

I had a look and tested this change with jvmci/graal on Solaris. It
compiles and runs without any error. Looks good to me.

Stefan



On 04/28/2017 01:48 PM, Patric Hedlin wrote:
> Dear all,
> 
> I would like to ask for help to review the following change/update:
> 
> Issue:    https://bugs.openjdk.java.net/browse/JDK-8172231
> 
> Webrev:   http://cr.openjdk.java.net/~neliasso/8172231/
> 
> 
> 
> 8172231: SPARC ISA/CPU feature detection is broken/insufficient (on
> Solaris).
> 
>     Updating SPARC feature/capability detection (incorporating changes
> from Martin Walsh).
>     More complete set of features as provided by 'getisax(2)' interface,
> propagated via JVMCI.
>     More robust hardware probing for additional features (up to Core S4).
>     Removing support for old, pre Niagara, hardware.
>     Removing support for old, pre 11.1, Solaris.
> 
>     Changed behaviour:
>     Changing SPARC setup for AllocatePrefetchLines and
> AllocateInstancePrefetchLines
>     such that they will (still) be doubled when cache-line size is small
> (32 bytes),
>     but more moderately increased on new/contemporary hardware (inc >= 50%).
>     Changing to default instruction fetch alignment based on derived
> caps. instead
>     of relying on default/configuration values.
> 
>     The above changes also subsumes:
>     8035146: assert(is_T_family(features) == is_niagara(features),
> "Niagara should be T series") is incorrect
>     8054979: Remove unnecessary defines in SPARC's
> VM_Version::platform_features
> 
> 
> Rationale:
> 
>     Current hardware detection on Solaris/SPARC is not up to date with
> the "latest" (here,
>     meaning commercially available server solutions, i.e. T7/M7). To
> facilitate improved
>     use of the new hardware features provided (by Core S3&S4) these
> capabilities need to
>     be recognised by the JVM.
> 
>     NOTE: This update is limited to Core S3&S4, i.e. not including Core
> S5. Proper Core S5
>     support will be added when regular testing and benchmarking
> resources are available,
>     i.e. regular testing need to include M8 hardware.
> 
> 
> Caveat:
> 
>     This update will introduce some redundancies into the code base,
> features and definitions
>     currently not used, as well as a (small) number of FIXMEs, addressed
> by subsequent bug or
>     feature updates/patches. Fujitsu HW is treated very conservatively.
> 
> 
> Testing:
> 
>     Mostly tested on JDK9 (RBT/hotspot/comp). Only local testing on
> JDK10 (jtreg/hotspot).
> 
> 
> Benchmarking:
> 
>     Benchmark reports from a limited set of runs can be found at:
> 
>     http://aurora.se.oracle.com/performance/reporting/report/patric.hedlin.TvM.jbb05
> 
>     http://aurora.se.oracle.com/performance/reporting/report/patric.hedlin.TvM.jvm08
> 
>     http://aurora.se.oracle.com/performance/reporting/report/patric.hedlin.TvM.octane.plus
> 
> 
>     (Limited availability of M7 hardware prevents complete suites/runs.)
> 
> 
> Best regards,
> Patric
>