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40 #include "visibility.h"
46 } /* fixes auto-indentation problems */
50 /* Currently identifiable CPU Vendors */
53 GMX_CPUID_VENDOR_CANNOTDETECT
, /* Should only be used if something fails */
54 GMX_CPUID_VENDOR_UNKNOWN
,
55 GMX_CPUID_VENDOR_INTEL
,
61 /* CPU feature/property list, to be used as indices into the feature array of the
62 * gmxcpuid_t data structure.
64 * To facilitate looking things up, we keep this list alphabetical.
65 * The list is NOT exhaustive - we have basically added stuff that might be
66 * useful in an application like Gromacs.
68 * AMD and Intel tend to share most architectural elements, and even if the
69 * flags might have to be detected in different ways (different cpuid registers),
70 * once the flag is present the functions should be identical. Unfortunately the
71 * trend right now (2012) seems to be that they are diverging. This means that
72 * we need to use specific flags to the compiler to maximize performance, and
73 * then the binaries might not be portable between Intel and AMD as they were
74 * before when we only needed to check for SSE and/or SSE2 support in Gromacs.
76 enum gmx_cpuid_feature
78 GMX_CPUID_FEATURE_CANNOTDETECT
, /* Flag set if we could not detect on this CPU */
79 GMX_CPUID_FEATURE_X86_AES
, /* x86 advanced encryption standard accel. */
80 GMX_CPUID_FEATURE_X86_APIC
, /* APIC support */
81 GMX_CPUID_FEATURE_X86_AVX
, /* Advanced vector extensions */
82 GMX_CPUID_FEATURE_X86_AVX2
, /* AVX2 including gather support (not used yet) */
83 GMX_CPUID_FEATURE_X86_CLFSH
, /* Supports CLFLUSH instruction */
84 GMX_CPUID_FEATURE_X86_CMOV
, /* Conditional move insn support */
85 GMX_CPUID_FEATURE_X86_CX8
, /* Supports CMPXCHG8B (8-byte compare-exchange) */
86 GMX_CPUID_FEATURE_X86_CX16
, /* Supports CMPXCHG16B (16-byte compare-exchg) */
87 GMX_CPUID_FEATURE_X86_F16C
, /* Supports 16-bit FP conversion instructions */
88 GMX_CPUID_FEATURE_X86_FMA
, /* Fused-multiply add support (mainly for AVX) */
89 GMX_CPUID_FEATURE_X86_FMA4
, /* 4-operand FMA, only on AMD for now */
90 GMX_CPUID_FEATURE_X86_HTT
, /* Hyper-Threading supported */
91 GMX_CPUID_FEATURE_X86_LAHF_LM
, /* LAHF/SAHF support in 64 bits */
92 GMX_CPUID_FEATURE_X86_MISALIGNSSE
, /* Support for misaligned SSE data instructions */
93 GMX_CPUID_FEATURE_X86_MMX
, /* MMX registers and instructions */
94 GMX_CPUID_FEATURE_X86_MSR
, /* Supports Intel model-specific-registers */
95 GMX_CPUID_FEATURE_X86_NONSTOP_TSC
, /* Invariant TSC (constant rate in ACPI states) */
96 GMX_CPUID_FEATURE_X86_PCID
, /* Process context identifier support */
97 GMX_CPUID_FEATURE_X86_PCLMULDQ
, /* Carry-less 64-bit multiplication supported */
98 GMX_CPUID_FEATURE_X86_PDCM
, /* Perfmon and Debug Capability */
99 GMX_CPUID_FEATURE_X86_PDPE1GB
, /* Support for 1GB pages */
100 GMX_CPUID_FEATURE_X86_POPCNT
, /* Supports the POPCNT (population count) insn */
101 GMX_CPUID_FEATURE_X86_PSE
, /* Supports 4MB-pages (page size extension) */
102 GMX_CPUID_FEATURE_X86_RDRND
, /* RDRAND high-quality hardware random numbers */
103 GMX_CPUID_FEATURE_X86_RDTSCP
, /* Serializing rdtscp instruction available */
104 GMX_CPUID_FEATURE_X86_SSE2
, /* SSE 2 */
105 GMX_CPUID_FEATURE_X86_SSE3
, /* SSE 3 */
106 GMX_CPUID_FEATURE_X86_SSE4A
, /* SSE 4A */
107 GMX_CPUID_FEATURE_X86_SSE4_1
, /* SSE 4.1 */
108 GMX_CPUID_FEATURE_X86_SSE4_2
, /* SSE 4.2 */
109 GMX_CPUID_FEATURE_X86_SSSE3
, /* Supplemental SSE3 */
110 GMX_CPUID_FEATURE_X86_TDT
, /* TSC deadline timer */
111 GMX_CPUID_FEATURE_X86_X2APIC
, /* Extended xAPIC Support */
112 GMX_CPUID_FEATURE_X86_XOP
, /* AMD extended instructions, only AMD for now */
117 /* Currently supported acceleration instruction sets, intrinsics or other similar combinations
118 * in Gromacs. There is not always a 1-to-1 correspondence with feature flags; on some AMD
119 * hardware we prefer to use 128bit AVX instructions (although 256-bit ones could be executed),
120 * and we still haven't written the AVX2 kernels.
122 enum gmx_cpuid_acceleration
124 GMX_CPUID_ACCELERATION_CANNOTDETECT
, /* Should only be used if something fails */
125 GMX_CPUID_ACCELERATION_NONE
,
126 GMX_CPUID_ACCELERATION_X86_SSE2
,
127 GMX_CPUID_ACCELERATION_X86_SSE4_1
,
128 GMX_CPUID_ACCELERATION_X86_AVX_128_FMA
,
129 GMX_CPUID_ACCELERATION_X86_AVX_256
,
130 GMX_CPUID_NACCELERATIONS
133 /* Text strings corresponding to CPU vendors */
136 gmx_cpuid_vendor_string
[GMX_CPUID_NVENDORS
];
138 /* Text strings for CPU feature indices */
140 gmx_cpuid_feature_string
[GMX_CPUID_NFEATURES
];
142 /* Text strings for Gromacs acceleration/instruction sets */
144 gmx_cpuid_acceleration_string
[GMX_CPUID_NACCELERATIONS
];
147 /* Abstract data type with CPU detection information. Set by gmx_cpuid_init(). */
148 typedef struct gmx_cpuid
*
152 /* Fill the data structure by using CPU detection instructions.
153 * Return 0 on success, 1 if something bad happened.
156 gmx_cpuid_init (gmx_cpuid_t
* cpuid
);
159 /* Return the vendor id as enumerated type. Use gmx_cpuid_vendor_string[]
160 * to get the corresponding text string.
163 enum gmx_cpuid_vendor
164 gmx_cpuid_vendor (gmx_cpuid_t cpuid
);
167 /* Return a constant pointer to the processor brand string. */
169 gmx_cpuid_brand (gmx_cpuid_t cpuid
);
172 /* Return processor family version. For a chip of version 1.2.3, this is 1 */
175 gmx_cpuid_family (gmx_cpuid_t cpuid
);
177 /* Return processor model version, For a chip of version 1.2.3, this is 2. */
180 gmx_cpuid_model (gmx_cpuid_t cpuid
);
182 /* Return processor stepping version, For a chip of version 1.2.3, this is 3. */
184 gmx_cpuid_stepping (gmx_cpuid_t cpuid
);
187 /* Check whether a particular CPUID feature is set.
188 * Returns 0 if flag "feature" is not set, 1 if the flag is set. We cannot use
189 * gmx_bool here since this file must be possible to compile without simple.h.
193 gmx_cpuid_feature (gmx_cpuid_t cpuid
,
194 enum gmx_cpuid_feature feature
);
197 /* Return pointers to cpu topology information.
199 * Important: CPU topology requires more OS support than most other
200 * functions in this file, including support for thread pinning to hardware.
201 * This means it will not work on some platforms, including e.g. Mac OS X.
202 * Thus, it is IMPERATIVE that you check the return value from this routine
203 * before doing anything with the information. It is only if the return
204 * value is zero that the data is valid.
206 * For the returned values we have:
207 * - nprocessors Total number of logical processors reported by OS
208 * - npackages Usually number of CPU sockets
209 * - ncores_per_package Number of cores in each package
210 * - nhwthreads_per_core Number of hardware threads per core; 2 for hyperthreading.
211 * - package_id Array with the package index for each logical cpu
212 * - core_id Array with local core index for each logical cpu
213 * - hwthread_id Array with local hwthread index for each logical cpu
214 * - locality_order Array with logical cpu numbers, sorted in order
215 * of physical and logical locality in the system.
217 * All arrays are of length nprocessors.
221 gmx_cpuid_topology(gmx_cpuid_t cpuid
,
224 int * ncores_per_package
,
225 int * nhwthreads_per_core
,
226 const int ** package_id
,
227 const int ** core_id
,
228 const int ** hwthread_id
,
229 const int ** locality_order
);
231 /* Enumerated values for x86 SMT enabled-status. Note that this does not refer
232 * to Hyper-Threading support (that is the flag GMX_CPUID_FEATURE_X86_HTT), but
233 * whether Hyper-Threading is _enabled_ and _used_ in bios right now.
235 enum gmx_cpuid_x86_smt
237 GMX_CPUID_X86_SMT_CANNOTDETECT
,
238 GMX_CPUID_X86_SMT_DISABLED
,
239 GMX_CPUID_X86_SMT_ENABLED
242 /* Returns the status of x86 SMT support. IMPORTANT: There are non-zero
243 * return values for this routine that still do not indicate supported and
244 * enabled smt/Hyper-Threading. You need to carefully check the return value
245 * against the enumerated type values to see what you are getting.
247 * Long-term, this functionality will move to a new hardware topology detection
248 * layer, but that will require a lot of new code and a working interface to the
249 * hwloc library. Surprisingly, there is no simple way to find out that
250 * Hyper-Threading is actually turned on without fully enumerating and checking
251 * all the cores, which we presently can only do on Linux. This means a couple
254 * 1) If you want to know whether your CPU _supports_ Hyper-Threading in the
255 * first place, check the GMX_CPUID_FEATURE_X86_HTT flag instead!
256 * 2) There are several scenarios where this routine will say that it cannot
257 * detect whether SMT is enabled and used right now.
258 * 3) If you need support on non-Linux x86, you have to write it :-)
259 * 4) Don't invest too much efforts, since this will be replaced with
260 * full hardware topology detection in the future.
261 * 5) Don't worry if the detection does not work. It is not a catastrophe, but
262 * but we get slightly better performance on x86 if we use Hyper-Threading
263 * cores in direct space, but not reciprocal space.
265 * Since this routine presently only supports Hyper-Threading we say X86_SMT
266 * in order not to give the impression we can detect any SMT. We haven't
267 * even tested the performance on other SMT implementations, so it is not
268 * obvious we shouldn't use SMT there.
270 * Note that you can get more complete topology information from
271 * gmx_cpuid_topology(), although that requires slightly more OS support.
274 enum gmx_cpuid_x86_smt
275 gmx_cpuid_x86_smt(gmx_cpuid_t cpuid
);
278 /* Formats a text string (up to n characters) from the data structure.
279 * The output will have max 80 chars between newline characters.
282 gmx_cpuid_formatstring (gmx_cpuid_t cpuid
,
287 /* Suggests a suitable gromacs acceleration based on the support in the
290 enum gmx_cpuid_acceleration
291 gmx_cpuid_acceleration_suggest (gmx_cpuid_t cpuid
);
294 /* Check if this binary was compiled with the same acceleration as we
295 * would suggest for the current hardware. Always print stats to the log file
296 * if it is non-NULL, and print a warning in stdout if we don't have a match.
299 gmx_cpuid_acceleration_check (gmx_cpuid_t cpuid
,
303 /* Release resources used by data structure. Note that the pointer to the
304 * CPU brand string will no longer be valid once this routine has been called.
307 gmx_cpuid_done (gmx_cpuid_t cpuid
);
317 #endif /* GMX_CPUID_H_ */