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  1. JDK
  2. JDK-8269825

[TESTBUG] Missing testing for x86 KNL platforms

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    • b30
    • x86

        In our testing environment we have x86 KVM virtualization with next CPUID features setting:

        CPU: total 8 (initial active 8) (4 cores per cpu, 2 threads per core) family 6 model 85 stepping 4 microcode 0x1, cx8, cmov, fxsr, ht, mmx, 3dnowpref, sse, sse2, sse3, ssse3, sse4.1, sse4.2, popcnt, lzcnt, tsc, avx, avx2, aes, erms, clmul, bmi1, bmi2, rtm, adx, avx512f, avx512cd, fma, vzeroupper, clflush, hv

        It is similar to Knights family of X86 Intel CPU (KNL) which does not support some of avx512 features (AVX512VL/BW) and have other restrictions. We may not have such kind of machines in our testing environment and may miss bugs as JBS history shows (look recent fixes for KNL).

        On other hand we have some Windows VM instances which have such configuration and limit avx512 instructions on CPU which supports full set. Recent bug JDK-8269775 shows such example.

        I suggest to add -XX:+UseKNLSetting x86 diagnostic flag to emulate KNL CPU settings in HotSpot JVM to test such configuration.

              kvn Vladimir Kozlov
              kvn Vladimir Kozlov
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