[aarch64-port-dev ] [10] RFR(S): JDK-8184943: AARCH64: Intrinsify hasNegatives

[Andrew Haley]

Hi,

On 20/07/17 11:03, Dmitrij Pochepko wrote:

> Please review this small webrev [1] that implements an enhancement [2] which adds has_negatives intrinsic to AARCH64 OpenJDK port. This intrinsic performs better than c2-compiled code for every array size tried:

Yay!  We're off to the races!

Yours:

Benchmark                       (length)  Mode  Cnt      Score   Error  Units
HasNegatives.loopingFastMethod         4  avgt    5   6680.619 ? 0.953  ns/op
HasNegatives.loopingFastMethod        31  avgt    5  12936.791 ? 1.599  ns/op
HasNegatives.loopingFastMethod        65  avgt    5  14604.253 ? 2.088  ns/op
HasNegatives.loopingFastMethod       101  avgt    5  19606.385 ? 7.751  ns/op
HasNegatives.loopingFastMethod       256  avgt    5  30858.498 ? 1.225  ns/op


Stuart's:

Benchmark                       (length)  Mode  Cnt      Score   Error  Units
HasNegatives.loopingFastMethod         4  avgt    5   5013.024 ? 0.572  ns/op
HasNegatives.loopingFastMethod        31  avgt    5   9186.044 ? 2.439  ns/op
HasNegatives.loopingFastMethod        65  avgt    5  13769.220 ? 1.879  ns/op
HasNegatives.loopingFastMethod       101  avgt    5  15854.385 ? 2.482  ns/op
HasNegatives.loopingFastMethod       256  avgt    5  26691.626 ? 3.523  ns/op

I didn't expect a big difference.  Note that the really important measurement
is on length ~31, which is very common.

Benchmark at http://cr.openjdk.java.net/~aph/HasNegativesBench/.  Test was on
APM.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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