e1b35da5e6
Enumerate AVX512 Half-precision floating point (FP16) CPUID feature flag. Compared with using FP32, using FP16 cut the number of bits required for storage in half, reducing the exponent from 8 bits to 5, and the mantissa from 23 bits to 10. Using FP16 also enables developers to train and run inference on deep learning models fast when all precision or magnitude (FP32) is not needed. A processor supports AVX512 FP16 if CPUID.(EAX=7,ECX=0):EDX[bit 23] is present. The AVX512 FP16 requires AVX512BW feature be implemented since the instructions for manipulating 32bit masks are associated with AVX512BW. The only in-kernel usage of this is kvm passthrough. The CPU feature flag is shown as "avx512_fp16" in /proc/cpuinfo. Signed-off-by: Kyung Min Park <kyung.min.park@intel.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Message-Id: <20201208033441.28207-2-kyung.min.park@intel.com> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.