Intel Xeon Phi
Knights Landing
Intel Knights Landing (2016) supports x86-64-v3.
- x86-64 level
- x86-64-v3
- Vendor
- Intel
- First products
- 2016
- Products
- Xeon Phi x200
- Segments
- GCC target
-march=knl
Implements AVX-512 without the BW, DQ and VL subsets, so it does not reach x86-64-v4. GCC 15 removed -march=knl.
Product lines
| Product line | Segment | Socket | Source |
|---|---|---|---|
| Xeon Phi x200 | server | LGA3647 (Xeon Phi) | intel.com |
Why not x86-64-v4?
Knights Landing lacks AVX512BW, AVX512DQ and AVX512VL, all of which x86-64-v4 requires.
Feature checklist
| Feature | Knights Landing | Enumerated by | Linux flag |
|---|---|---|---|
| x86-64-v1 | |||
| CMOV | Yes | CPUID.01H:EDX[15] | cmov |
| CX8 | Yes | CPUID.01H:EDX[8] | cx8 |
| FPU | Yes | CPUID.01H:EDX[0] | fpu |
| FXSR | Yes | CPUID.01H:EDX[24] | fxsr |
| MMX | Yes | CPUID.01H:EDX[23] | mmx |
| OSFXSR via FXSR | Yes | CPUID.01H:EDX[24] | fxsr |
| SCE | Yes | CPUID.80000001H:EDX[11] | syscall |
| SSE | Yes | CPUID.01H:EDX[25] | sse |
| SSE2 | Yes | CPUID.01H:EDX[26] | sse2 |
| x86-64-v2 | |||
| CMPXCHG16B | Yes | CPUID.01H:ECX[13] | cx16 |
| LAHF-SAHF | Yes | CPUID.80000001H:ECX[0] | lahf_lm |
| POPCNT | Yes | CPUID.01H:ECX[23] | popcnt |
| SSE3 | Yes | CPUID.01H:ECX[0] | pni |
| SSE4.1 | Yes | CPUID.01H:ECX[19] | sse4_1 |
| SSE4.2 | Yes | CPUID.01H:ECX[20] | sse4_2 |
| SSSE3 | Yes | CPUID.01H:ECX[9] | ssse3 |
| x86-64-v3 | |||
| AVX | Yes | CPUID.01H:ECX[28] | avx |
| AVX2 | Yes | CPUID.(EAX=07H,ECX=0):EBX[5] | avx2 |
| BMI1 | Yes | CPUID.(EAX=07H,ECX=0):EBX[3] | bmi1 |
| BMI2 | Yes | CPUID.(EAX=07H,ECX=0):EBX[8] | bmi2 |
| F16C | Yes | CPUID.01H:ECX[29] | f16c |
| FMA | Yes | CPUID.01H:ECX[12] | fma |
| LZCNT | Yes | CPUID.80000001H:ECX[5] | abm |
| MOVBE | Yes | CPUID.01H:ECX[22] | movbe |
| OSXSAVE via XSAVE | Yes | CPUID.01H:ECX[26] | xsave |
| x86-64-v4 | |||
| AVX512F | Yes | CPUID.(EAX=07H,ECX=0):EBX[16] | avx512f |
| AVX512BW | No | CPUID.(EAX=07H,ECX=0):EBX[30] | avx512bw |
| AVX512CD | Yes | CPUID.(EAX=07H,ECX=0):EBX[28] | avx512cd |
| AVX512DQ | No | CPUID.(EAX=07H,ECX=0):EBX[17] | avx512dq |
| AVX512VL | No | CPUID.(EAX=07H,ECX=0):EBX[31] | avx512vl |
Other extensions
Notable extensions outside the x86-64 levels. Vendors sometimes disable these on individual models. Linked names lead to the extension's instructions.
Known vulnerabilities
The CVEs that the sources of the vulnerability list name as affecting Knights Landing, in all of its models or in some of them.
- CVE-2018-12126 Microarchitectural Data Sampling: Microarchitectural Store Buffer Data Sampling
- CVE-2017-5754 Meltdown: Rogue Data Cache Load
- CVE-2017-5753 Spectre variant 1: Bounds Check Bypass
- CVE-2017-5715 Spectre variant 2: Branch Target Injection
Other Intel Xeon Phi microarchitectures
- Knights Landing 2016 v3
- Knights Mill 2017 v3
Sources
- GCC -march=knl feature set (PTA_KNL)
- Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 4, 335592-093, Table 2-1: Model 06_57H: Xeon Phi 3200, 5200 and 7200 series, Knights Landing.
- Intel ARK: Products formerly Knights Landing: Launch dates; the earliest is Q2'16 (Xeon Phi 7210).
- GCC 15 release notes, IA-32/x86-64: GCC 15 removed support for the Xeon Phi processors: -march=knl and -march=knm.