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45 } /* fixes auto-indentation problems */
49 /* Currently identifiable CPU Vendors */
52 GMX_CPUID_VENDOR_CANNOTDETECT, /* Should only be used if something fails */
53 GMX_CPUID_VENDOR_UNKNOWN,
54 GMX_CPUID_VENDOR_INTEL,
56 GMX_CPUID_VENDOR_FUJITSU,
63 /* CPU feature/property list, to be used as indices into the feature array of the
64 * gmxcpuid_t data structure.
66 * To facilitate looking things up, we keep this list alphabetical.
67 * The list is NOT exhaustive - we have basically added stuff that might be
68 * useful in an application like Gromacs.
70 * AMD and Intel tend to share most architectural elements, and even if the
71 * flags might have to be detected in different ways (different cpuid registers),
72 * once the flag is present the functions should be identical. Unfortunately the
73 * trend right now (2012) seems to be that they are diverging. This means that
74 * we need to use specific flags to the compiler to maximize performance, and
75 * then the binaries might not be portable between Intel and AMD as they were
76 * before when we only needed to check for SSE and/or SSE2 support in Gromacs.
78 enum gmx_cpuid_feature
80 GMX_CPUID_FEATURE_CANNOTDETECT, /* Flag set if we could not detect on this CPU */
81 GMX_CPUID_FEATURE_X86_AES, /* x86 advanced encryption standard accel. */
82 GMX_CPUID_FEATURE_X86_APIC, /* APIC support */
83 GMX_CPUID_FEATURE_X86_AVX, /* Advanced vector extensions */
84 GMX_CPUID_FEATURE_X86_AVX2, /* AVX2 including gather support (not used yet) */
85 GMX_CPUID_FEATURE_X86_CLFSH, /* Supports CLFLUSH instruction */
86 GMX_CPUID_FEATURE_X86_CMOV, /* Conditional move insn support */
87 GMX_CPUID_FEATURE_X86_CX8, /* Supports CMPXCHG8B (8-byte compare-exchange) */
88 GMX_CPUID_FEATURE_X86_CX16, /* Supports CMPXCHG16B (16-byte compare-exchg) */
89 GMX_CPUID_FEATURE_X86_F16C, /* Supports 16-bit FP conversion instructions */
90 GMX_CPUID_FEATURE_X86_FMA, /* Fused-multiply add support (mainly for AVX) */
91 GMX_CPUID_FEATURE_X86_FMA4, /* 4-operand FMA, only on AMD for now */
92 GMX_CPUID_FEATURE_X86_HTT, /* Hyper-Threading supported */
93 GMX_CPUID_FEATURE_X86_LAHF_LM, /* LAHF/SAHF support in 64 bits */
94 GMX_CPUID_FEATURE_X86_MISALIGNSSE, /* Support for misaligned SSE data instructions */
95 GMX_CPUID_FEATURE_X86_MMX, /* MMX registers and instructions */
96 GMX_CPUID_FEATURE_X86_MSR, /* Supports Intel model-specific-registers */
97 GMX_CPUID_FEATURE_X86_NONSTOP_TSC, /* Invariant TSC (constant rate in ACPI states) */
98 GMX_CPUID_FEATURE_X86_PCID, /* Process context identifier support */
99 GMX_CPUID_FEATURE_X86_PCLMULDQ, /* Carry-less 64-bit multiplication supported */
100 GMX_CPUID_FEATURE_X86_PDCM, /* Perfmon and Debug Capability */
101 GMX_CPUID_FEATURE_X86_PDPE1GB, /* Support for 1GB pages */
102 GMX_CPUID_FEATURE_X86_POPCNT, /* Supports the POPCNT (population count) insn */
103 GMX_CPUID_FEATURE_X86_PSE, /* Supports 4MB-pages (page size extension) */
104 GMX_CPUID_FEATURE_X86_RDRND, /* RDRAND high-quality hardware random numbers */
105 GMX_CPUID_FEATURE_X86_RDTSCP, /* Serializing rdtscp instruction available */
106 GMX_CPUID_FEATURE_X86_SSE2, /* SSE 2 */
107 GMX_CPUID_FEATURE_X86_SSE3, /* SSE 3 */
108 GMX_CPUID_FEATURE_X86_SSE4A, /* SSE 4A */
109 GMX_CPUID_FEATURE_X86_SSE4_1, /* SSE 4.1 */
110 GMX_CPUID_FEATURE_X86_SSE4_2, /* SSE 4.2 */
111 GMX_CPUID_FEATURE_X86_SSSE3, /* Supplemental SSE3 */
112 GMX_CPUID_FEATURE_X86_TDT, /* TSC deadline timer */
113 GMX_CPUID_FEATURE_X86_X2APIC, /* Extended xAPIC Support */
114 GMX_CPUID_FEATURE_X86_XOP, /* AMD extended instructions, only AMD for now */
115 GMX_CPUID_FEATURE_ARM_NEON, /* 32-bit ARM NEON */
116 GMX_CPUID_FEATURE_ARM_NEON_ASIMD, /* 64-bit ARM AArch64 Advanced SIMD */
121 /* Currently supported SIMD instruction sets, intrinsics or other similar combinations
122 * in Gromacs. There is not always a 1-to-1 correspondence with feature flags; on some AMD
123 * hardware we prefer to use 128bit AVX instructions (although 256-bit ones could be executed),
124 * and we still haven't written the AVX2 kernels.
128 GMX_CPUID_SIMD_CANNOTDETECT, /* Should only be used if something fails */
130 GMX_CPUID_SIMD_REFERENCE,
131 GMX_CPUID_SIMD_X86_SSE2,
132 GMX_CPUID_SIMD_X86_SSE4_1,
133 GMX_CPUID_SIMD_X86_AVX_128_FMA,
134 GMX_CPUID_SIMD_X86_AVX_256,
135 GMX_CPUID_SIMD_X86_AVX2_256,
136 GMX_CPUID_SIMD_SPARC64_HPC_ACE,
137 GMX_CPUID_SIMD_IBM_QPX,
138 GMX_CPUID_SIMD_ARM_NEON,
139 GMX_CPUID_SIMD_ARM_NEON_ASIMD,
143 /* Text strings corresponding to CPU vendors */
145 gmx_cpuid_vendor_string[GMX_CPUID_NVENDORS];
147 /* Text strings for CPU feature indices */
149 gmx_cpuid_feature_string[GMX_CPUID_NFEATURES];
151 /* Text strings for Gromacs SIMD instruction sets */
153 gmx_cpuid_simd_string[GMX_CPUID_NSIMD];
156 /* Abstract data type with CPU detection information. Set by gmx_cpuid_init(). */
157 typedef struct gmx_cpuid *
161 /* Fill the data structure by using CPU detection instructions.
162 * Return 0 on success, 1 if something bad happened.
165 gmx_cpuid_init (gmx_cpuid_t * cpuid);
168 /* Return the vendor id as enumerated type. Use gmx_cpuid_vendor_string[]
169 * to get the corresponding text string.
171 enum gmx_cpuid_vendor
172 gmx_cpuid_vendor (gmx_cpuid_t cpuid);
175 /* Return a constant pointer to the processor brand string. */
177 gmx_cpuid_brand (gmx_cpuid_t cpuid);
180 /* Return processor family version. For a chip of version 1.2.3, this is 1 */
182 gmx_cpuid_family (gmx_cpuid_t cpuid);
184 /* Return processor model version, For a chip of version 1.2.3, this is 2. */
186 gmx_cpuid_model (gmx_cpuid_t cpuid);
188 /* Return processor stepping version, For a chip of version 1.2.3, this is 3. */
190 gmx_cpuid_stepping (gmx_cpuid_t cpuid);
193 /* Check whether a particular CPUID feature is set.
194 * Returns 0 if flag "feature" is not set, 1 if the flag is set. We cannot use
195 * gmx_bool here since this file must be possible to compile without simple.h.
198 gmx_cpuid_feature (gmx_cpuid_t cpuid,
199 enum gmx_cpuid_feature feature);
202 /* Return pointers to cpu topology information.
204 * Important: CPU topology requires more OS support than most other
205 * functions in this file, including support for thread pinning to hardware.
206 * This means it will not work on some platforms, including e.g. Mac OS X.
207 * Thus, it is IMPERATIVE that you check the return value from this routine
208 * before doing anything with the information. It is only if the return
209 * value is zero that the data is valid.
211 * For the returned values we have:
212 * - nprocessors Total number of logical processors reported by OS
213 * - npackages Usually number of CPU sockets
214 * - ncores_per_package Number of cores in each package
215 * - nhwthreads_per_core Number of hardware threads per core; 2 for hyperthreading.
216 * - package_id Array with the package index for each logical cpu
217 * - core_id Array with local core index for each logical cpu
218 * - hwthread_id Array with local hwthread index for each logical cpu
219 * - locality_order Array with logical cpu numbers, sorted in order
220 * of physical and logical locality in the system.
222 * All arrays are of length nprocessors.
225 gmx_cpuid_topology(gmx_cpuid_t cpuid,
228 int * ncores_per_package,
229 int * nhwthreads_per_core,
230 const int ** package_id,
231 const int ** core_id,
232 const int ** hwthread_id,
233 const int ** locality_order);
235 /* Enumerated values for x86 SMT enabled-status. Note that this does not refer
236 * to Hyper-Threading support (that is the flag GMX_CPUID_FEATURE_X86_HTT), but
237 * whether Hyper-Threading is _enabled_ and _used_ in bios right now.
239 enum gmx_cpuid_x86_smt
241 GMX_CPUID_X86_SMT_CANNOTDETECT,
242 GMX_CPUID_X86_SMT_DISABLED,
243 GMX_CPUID_X86_SMT_ENABLED
246 /* Returns the status of x86 SMT support. IMPORTANT: There are non-zero
247 * return values for this routine that still do not indicate supported and
248 * enabled smt/Hyper-Threading. You need to carefully check the return value
249 * against the enumerated type values to see what you are getting.
251 * Long-term, this functionality will move to a new hardware topology detection
252 * layer, but that will require a lot of new code and a working interface to the
253 * hwloc library. Surprisingly, there is no simple way to find out that
254 * Hyper-Threading is actually turned on without fully enumerating and checking
255 * all the cores, which we presently can only do on Linux. This means a couple
258 * 1) If you want to know whether your CPU _supports_ Hyper-Threading in the
259 * first place, check the GMX_CPUID_FEATURE_X86_HTT flag instead!
260 * 2) There are several scenarios where this routine will say that it cannot
261 * detect whether SMT is enabled and used right now.
262 * 3) If you need support on non-Linux x86, you have to write it :-)
263 * 4) Don't invest too much efforts, since this will be replaced with
264 * full hardware topology detection in the future.
265 * 5) Don't worry if the detection does not work. It is not a catastrophe, but
266 * but we get slightly better performance on x86 if we use Hyper-Threading
267 * cores in direct space, but not reciprocal space.
269 * Since this routine presently only supports Hyper-Threading we say X86_SMT
270 * in order not to give the impression we can detect any SMT. We haven't
271 * even tested the performance on other SMT implementations, so it is not
272 * obvious we shouldn't use SMT there.
274 * Note that you can get more complete topology information from
275 * gmx_cpuid_topology(), although that requires slightly more OS support.
277 enum gmx_cpuid_x86_smt
278 gmx_cpuid_x86_smt(gmx_cpuid_t cpuid);
281 /* Formats a text string (up to n characters) from the data structure.
282 * The output will have max 80 chars between newline characters.
285 gmx_cpuid_formatstring (gmx_cpuid_t cpuid,
290 /* Suggests a suitable gromacs SIMD based on the support in the
294 gmx_cpuid_simd_suggest (gmx_cpuid_t cpuid);
297 /* Check if this binary was compiled with the same SIMD instructions as we
298 * would suggest for the current hardware. Always print stats to the log file
299 * if it is non-NULL, and if we don't have a match, print a warning in log
300 * (if non-NULL) and if print_to_stderr!=0 also to stderr.
303 gmx_cpuid_simd_check (gmx_cpuid_t cpuid,
305 int print_to_stderr);
308 /* Release resources used by data structure. Note that the pointer to the
309 * CPU brand string will no longer be valid once this routine has been called.
312 gmx_cpuid_done (gmx_cpuid_t cpuid);
322 #endif /* GMX_CPUID_H_ */