RFR (M) 8175369: [ppc] Provide intrinsic implementation for CRC32C
martin.doerr at sap.com
Fri Mar 3 16:33:37 UTC 2017
thank you very much for implementing it for PPC64, too.
Unfortunately, the patch doesn’t apply cleanly any more (due to clashes with other changes).
But it should be easy to fix.
The copyright change of templateInterpreterGenerator_ppc.cpp doesn’t fit any more (same is true for s390 webrev).
In addition, the PPC64 change was not build on top of the s390 one. The shared code change in c1_Compiler.cpp needs to be adapted in this change and pushed after the s390 one.
As the change is very similar to what you’ve done on s390, it already contains what I had requested in the other review.
I only have a comment on the macroAssembler part:
I didn't review kernel_crc32_2word as it is no longer used and should get removed sooner or later (not necessarily with this change).
kernel_crc32_1word contains an s390 comment "ahgi".
Besides that, it looks good to me.
Thanks and best regards,
From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-bounces at openjdk.java.net] On Behalf Of Schmidt, Lutz
Sent: Donnerstag, 2. März 2017 17:24
To: hotspot-compiler-dev at openjdk.java.net
Subject: RFR (M) 8175369: [ppc] Provide intrinsic implementation for CRC32C
may I kindly request reviews for my medium size enhancement? Further down the road, I would need a sponsor, too.
This intrinsic implementation provides some performance benefit over the standard Java implementation. It uses only well-known “standard” instructions, available on all supported POWER cpus. Being very similar to the CRC32 intrinsics, it was tried to share as much code as possible between these two.
Performance was observed to increase up to 2.0x, depending on the length of the byte array fed into CRC32C. Short byte arrays benefit more. That is due to the fact that the Java implementation of CRC32C is well inlined and optimized by the JIT, at least with my simple micro benchmarks.
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