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Diffstat (limited to 'doc/guides/rel_notes/known_issues.rst')
| -rw-r--r-- | doc/guides/rel_notes/known_issues.rst | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst index a1face9c..358dfa32 100644 --- a/doc/guides/rel_notes/known_issues.rst +++ b/doc/guides/rel_notes/known_issues.rst @@ -826,3 +826,38 @@ Kernel crash when hot-unplug igb_uio device while DPDK application is running **Driver/Module**: ``igb_uio`` module. + + +AVX-512 support disabled +------------------------ + +**Description**: + ``AVX-512`` support has been disabled on some conditions. + This shouldn't be confused with ``CONFIG_RTE_ENABLE_AVX512`` config option which is already + disabled by default. This config option defines if ``AVX-512`` specific implementations of + some file to be used or not. What has been disabled is compiler feature to produce ``AVX-512`` + instructions from any source code. + + On DPDK v18.11 ``AVX-512`` is disabled for all ``GCC`` builds which reported to cause a performance + drop. + + On DPDK v19.02 ``AVX-512`` disable scope is reduced to ``GCC`` and ``binutils version 2.30`` based + on information accured from the GCC community defect. + +**Reason**: + Generated ``AVX-512`` code cause crash: + https://bugs.dpdk.org/show_bug.cgi?id=97 + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096 + +**Resolution/Workaround**: + * Update ``binutils`` to newer version than ``2.30``. + + OR + + * Use different compiler, like ``clang`` for this case. + +**Affected Environment/Platform**: + ``GCC`` and ``binutils version 2.30``. + +**Driver/Module**: + ALL. |