Hello,
On 9/5/2018 6:12 AM, Severin Gehwolf wrote:
Hi, Cross-posting this review-thread on core-libs-dev and build-dev as this is a build change, but affects fdlibm which is core-libs. With JDK-8170153 optimization for fdlibm code has been turned on for ppc64 s390 and aarch64. This patch intends to turn it on on all arches on Linux. I've not observed any precision issues. Is there a good reason to not use -O3 -ffp-contract=off everywhere? Bug: https://bugs.openjdk.java.net/browse/JDK-8210416 webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210416/webrev.01/ Testing: - java/lang/Math, java/lang/StrictMath tests (all pass). - Currently running through submit repo. A simple micro benchmark from JDK-8170153[1] shows these numbers for StrictMath: Function | before | after ---------------------------------------------- sin | 0m33.382s | 0m18.731s cos | 0m31.562s | 0m18.796s tan | 0m33.657s | 0m21.093s atan | 0m5.714s | 0m4.902s log | 0m6.212s | 0m4.439s log10 | 0m7.946s | 0m5.543s sqrt | 0m0.481s | 0m0.449s cbrt | 0m5.295s | 0m5.214s tanh | 0m1.404s | 0m1.307s log1p | 0m6.457s | 0m5.131s IEEEremainder | 0m10.629s | 0m6.048s atan2 | 0m8.037s | 0m5.668s hypot | 0m2.171s | 0m2.147s
Note that pow (JDK-8134795), hypot (JDK-7130085), cbrt (JDK-8136799), and exp (JDK-8139688), have been ported to Java as of JDK 9. The sqrt method is commonly handled as an intrinsic.
Testing that was not geared toward finding precision/rounding issues would be unlikely to find them.
I don't see the sources of the microbenchmark in JDK-8170153. Cheers, -Joe
