doc: announce disabling GCC AVX512F as known issue

Document that AVX512F has been disabled for GCC builds [1] and document
its potential implications on release notes, known issue section.

[1]
Commit 8d07c82b23 ("mk: disable gcc AVX512F support")

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>
This commit is contained in:
Ferruh Yigit 2018-11-20 12:50:31 +00:00 committed by Thomas Monjalon
parent e3e363a2d1
commit aa47e0b7d4

View File

@ -584,6 +584,17 @@ Known Issues
* IBM Power8 is not supported by this release of DPDK. IBM Power9 is supported. * IBM Power8 is not supported by this release of DPDK. IBM Power9 is supported.
* ``AVX-512`` support has been disabled for ``GCC`` builds [1] because of a crash [2].
This can affect ``native`` machine type build targets on the platforms that support
``AVX512F`` like ``Intel Skylake`` processors, and can cause a possible performance drop.
The immediate workaround is to use ``clang`` compiler on these platforms.
Issue has been identified as a GCC defect and reported to GCC community [3]. Further
actions will be taken based on the GCC defect result.
[1]: Commit 8d07c82b239f ("mk: disable gcc AVX512F support")
[2]: https://bugs.dpdk.org/show_bug.cgi?id=97
[3]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096
Tested Platforms Tested Platforms
---------------- ----------------