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37 #include "detecthardware.h"
49 #include "gromacs/compat/pointers.h"
50 #include "gromacs/gpu_utils/gpu_utils.h"
51 #include "gromacs/hardware/cpuinfo.h"
52 #include "gromacs/hardware/hardwaretopology.h"
53 #include "gromacs/hardware/hw_info.h"
54 #include "gromacs/simd/support.h"
55 #include "gromacs/utility/basedefinitions.h"
56 #include "gromacs/utility/basenetwork.h"
57 #include "gromacs/utility/baseversion.h"
58 #include "gromacs/utility/cstringutil.h"
59 #include "gromacs/utility/exceptions.h"
60 #include "gromacs/utility/fatalerror.h"
61 #include "gromacs/utility/gmxassert.h"
62 #include "gromacs/utility/logger.h"
63 #include "gromacs/utility/mutex.h"
64 #include "gromacs/utility/physicalnodecommunicator.h"
66 #include "architecture.h"
69 # include <unistd.h> // sysconf()
72 gmx_hw_info_t::gmx_hw_info_t(std::unique_ptr<gmx::CpuInfo> cpuInfo,
73 std::unique_ptr<gmx::HardwareTopology> hardwareTopology)
74 : cpuInfo(std::move(cpuInfo)),
75 hardwareTopology(std::move(hardwareTopology))
79 gmx_hw_info_t::~gmx_hw_info_t()
81 free_gpu_info(&gpu_info);
87 //! Convenience macro to help us avoid ifdefs each time we use sysconf
88 #if !defined(_SC_NPROCESSORS_ONLN) && defined(_SC_NPROC_ONLN)
89 # define _SC_NPROCESSORS_ONLN _SC_NPROC_ONLN
92 //! Convenience macro to help us avoid ifdefs each time we use sysconf
93 #if !defined(_SC_NPROCESSORS_CONF) && defined(_SC_NPROC_CONF)
94 # define _SC_NPROCESSORS_CONF _SC_NPROC_CONF
97 /*! \brief Information about the hardware of all nodes (common to all threads in this process).
99 * This information is constructed only when required, but thereafter
100 * its lifetime is that of the whole process, potentially across
101 * multiple successive simulation parts. It's wise to ensure that only
102 * one thread can create the information, but thereafter they can all
103 * read it without e.g. needing a std::shared_ptr to ensure its
104 * lifetime exceeds that of the thread. */
105 static std::unique_ptr<gmx_hw_info_t> g_hardwareInfo;
106 //! A mutex to protect the hwinfo structure
107 static Mutex g_hardwareInfoMutex;
109 //! Detect GPUs, if that makes sense to attempt.
110 static void gmx_detect_gpus(const gmx::MDLogger &mdlog,
111 const PhysicalNodeCommunicator &physicalNodeComm,
112 compat::not_null<gmx_hw_info_t *> hardwareInfo)
114 hardwareInfo->gpu_info.bDetectGPUs = canPerformGpuDetection();
116 if (!hardwareInfo->gpu_info.bDetectGPUs)
121 bool isMasterRankOfPhysicalNode = true;
123 isMasterRankOfPhysicalNode = (physicalNodeComm.rank_ == 0);
125 // We choose to run the detection only once with thread-MPI and
126 // use a mutex to enforce it.
127 GMX_UNUSED_VALUE(physicalNodeComm);
128 isMasterRankOfPhysicalNode = true;
131 /* The OpenCL support requires us to run detection on all ranks.
132 * With CUDA we don't need to, and prefer to detect on one rank
133 * and send the information to the other ranks over MPI. */
134 bool allRanksMustDetectGpus = (GMX_GPU == GMX_GPU_OPENCL);
135 bool gpusCanBeDetected = false;
136 if (isMasterRankOfPhysicalNode || allRanksMustDetectGpus)
138 std::string errorMessage;
139 gpusCanBeDetected = isGpuDetectionFunctional(&errorMessage);
140 if (!gpusCanBeDetected)
142 GMX_LOG(mdlog.info).asParagraph().appendTextFormatted(
143 "NOTE: Detection of GPUs failed. The API reported:\n"
145 " GROMACS cannot run tasks on a GPU.",
146 errorMessage.c_str());
150 if (gpusCanBeDetected)
152 findGpus(&hardwareInfo->gpu_info);
153 // No need to tell the user anything at this point, they get a
154 // hardware report later.
158 if (!allRanksMustDetectGpus)
160 /* Broadcast the GPU info to the other ranks within this node */
161 MPI_Bcast(&hardwareInfo->gpu_info.n_dev, 1, MPI_INT, 0, physicalNodeComm.comm_);
163 if (hardwareInfo->gpu_info.n_dev > 0)
167 dev_size = hardwareInfo->gpu_info.n_dev*sizeof_gpu_dev_info();
169 if (!isMasterRankOfPhysicalNode)
171 hardwareInfo->gpu_info.gpu_dev =
172 (struct gmx_device_info_t *)malloc(dev_size);
174 MPI_Bcast(hardwareInfo->gpu_info.gpu_dev, dev_size, MPI_BYTE,
175 0, physicalNodeComm.comm_);
176 MPI_Bcast(&hardwareInfo->gpu_info.n_dev_compatible, 1, MPI_INT,
177 0, physicalNodeComm.comm_);
183 //! Reduce the locally collected \p hardwareInfo over MPI ranks
184 static void gmx_collect_hardware_mpi(const gmx::CpuInfo &cpuInfo,
185 const PhysicalNodeCommunicator &physicalNodeComm,
186 compat::not_null<gmx_hw_info_t *> hardwareInfo)
188 const int ncore = hardwareInfo->hardwareTopology->numberOfCores();
189 /* Zen has family=23, for now we treat future AMD CPUs like Zen
190 * and Hygon Dhyana like Zen */
191 const bool cpuIsAmdZen = ((cpuInfo.vendor() == CpuInfo::Vendor::Amd &&
192 cpuInfo.family() >= 23) ||
193 cpuInfo.vendor() == CpuInfo::Vendor::Hygon);
196 int nhwthread, ngpu, i;
199 nhwthread = hardwareInfo->nthreads_hw_avail;
200 ngpu = hardwareInfo->gpu_info.n_dev_compatible;
201 /* Create a unique hash of the GPU type(s) in this node */
203 /* Here it might be better to only loop over the compatible GPU, but we
204 * don't have that information available and it would also require
205 * removing the device ID from the device info string.
207 for (i = 0; i < hardwareInfo->gpu_info.n_dev; i++)
211 /* Since the device ID is incorporated in the hash, the order of
212 * the GPUs affects the hash. Also two identical GPUs won't give
213 * a gpu_hash of zero after XORing.
215 get_gpu_device_info_string(stmp, hardwareInfo->gpu_info, i);
216 gpu_hash ^= gmx_string_fullhash_func(stmp, gmx_string_hash_init);
219 constexpr int numElementsCounts = 4;
220 std::array<int, numElementsCounts> countsReduced;
222 std::array<int, numElementsCounts> countsLocal = {{0}};
223 // Organize to sum values from only one rank within each node,
224 // so we get the sum over all nodes.
225 bool isMasterRankOfPhysicalNode = (physicalNodeComm.rank_ == 0);
226 if (isMasterRankOfPhysicalNode)
229 countsLocal[1] = ncore;
230 countsLocal[2] = nhwthread;
231 countsLocal[3] = ngpu;
234 MPI_Allreduce(countsLocal.data(), countsReduced.data(), countsLocal.size(),
235 MPI_INT, MPI_SUM, MPI_COMM_WORLD);
238 constexpr int numElementsMax = 11;
239 std::array<int, numElementsMax> maxMinReduced;
241 std::array<int, numElementsMax> maxMinLocal;
242 /* Store + and - values for all ranks,
243 * so we can get max+min with one MPI call.
245 maxMinLocal[0] = ncore;
246 maxMinLocal[1] = nhwthread;
247 maxMinLocal[2] = ngpu;
248 maxMinLocal[3] = static_cast<int>(gmx::simdSuggested(cpuInfo));
249 maxMinLocal[4] = gpu_hash;
250 maxMinLocal[5] = -maxMinLocal[0];
251 maxMinLocal[6] = -maxMinLocal[1];
252 maxMinLocal[7] = -maxMinLocal[2];
253 maxMinLocal[8] = -maxMinLocal[3];
254 maxMinLocal[9] = -maxMinLocal[4];
255 maxMinLocal[10] = (cpuIsAmdZen ? 1 : 0);
257 MPI_Allreduce(maxMinLocal.data(), maxMinReduced.data(), maxMinLocal.size(),
258 MPI_INT, MPI_MAX, MPI_COMM_WORLD);
261 hardwareInfo->nphysicalnode = countsReduced[0];
262 hardwareInfo->ncore_tot = countsReduced[1];
263 hardwareInfo->ncore_min = -maxMinReduced[5];
264 hardwareInfo->ncore_max = maxMinReduced[0];
265 hardwareInfo->nhwthread_tot = countsReduced[2];
266 hardwareInfo->nhwthread_min = -maxMinReduced[6];
267 hardwareInfo->nhwthread_max = maxMinReduced[1];
268 hardwareInfo->ngpu_compatible_tot = countsReduced[3];
269 hardwareInfo->ngpu_compatible_min = -maxMinReduced[7];
270 hardwareInfo->ngpu_compatible_max = maxMinReduced[2];
271 hardwareInfo->simd_suggest_min = -maxMinReduced[8];
272 hardwareInfo->simd_suggest_max = maxMinReduced[3];
273 hardwareInfo->bIdenticalGPUs = (maxMinReduced[4] == -maxMinReduced[9]);
274 hardwareInfo->haveAmdZenCpu = (maxMinReduced[10] > 0);
276 /* All ranks use the same pointer, protected by a mutex in the caller */
277 hardwareInfo->nphysicalnode = 1;
278 hardwareInfo->ncore_tot = ncore;
279 hardwareInfo->ncore_min = ncore;
280 hardwareInfo->ncore_max = ncore;
281 hardwareInfo->nhwthread_tot = hardwareInfo->nthreads_hw_avail;
282 hardwareInfo->nhwthread_min = hardwareInfo->nthreads_hw_avail;
283 hardwareInfo->nhwthread_max = hardwareInfo->nthreads_hw_avail;
284 hardwareInfo->ngpu_compatible_tot = hardwareInfo->gpu_info.n_dev_compatible;
285 hardwareInfo->ngpu_compatible_min = hardwareInfo->gpu_info.n_dev_compatible;
286 hardwareInfo->ngpu_compatible_max = hardwareInfo->gpu_info.n_dev_compatible;
287 hardwareInfo->simd_suggest_min = static_cast<int>(simdSuggested(cpuInfo));
288 hardwareInfo->simd_suggest_max = static_cast<int>(simdSuggested(cpuInfo));
289 hardwareInfo->bIdenticalGPUs = TRUE;
290 hardwareInfo->haveAmdZenCpu = cpuIsAmdZen;
291 GMX_UNUSED_VALUE(physicalNodeComm);
295 /*! \brief Utility that does dummy computing for max 2 seconds to spin up cores
297 * This routine will check the number of cores configured and online
298 * (using sysconf), and the spins doing dummy compute operations for up to
299 * 2 seconds, or until all cores have come online. This can be used prior to
300 * hardware detection for platforms that take unused processors offline.
302 * This routine will not throw exceptions.
305 spinUpCore() noexcept
307 #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_CONF) && defined(_SC_NPROCESSORS_ONLN)
309 int countConfigured = sysconf(_SC_NPROCESSORS_CONF); // noexcept
310 auto start = std::chrono::steady_clock::now(); // noexcept
312 while (sysconf(_SC_NPROCESSORS_ONLN) < countConfigured &&
313 std::chrono::steady_clock::now() - start < std::chrono::seconds(2))
315 for (int i = 1; i < 10000; i++)
323 printf("This cannot happen, but prevents loop from being optimized away.");
328 /*! \brief Prepare the system before hardware topology detection
330 * This routine should perform any actions we want to put the system in a state
331 * where we want it to be before detecting the hardware topology. For most
332 * processors there is nothing to do, but some architectures (in particular ARM)
333 * have support for taking configured cores offline, which will make them disappear
334 * from the online processor count.
336 * This routine checks if there is a mismatch between the number of cores
337 * configured and online, and in that case we issue a small workload that
338 * attempts to wake sleeping cores before doing the actual detection.
340 * This type of mismatch can also occur for x86 or PowerPC on Linux, if SMT has only
341 * been disabled in the kernel (rather than bios). Since those cores will never
342 * come online automatically, we currently skip this test for x86 & PowerPC to
343 * avoid wasting 2 seconds. We also skip the test if there is no thread support.
345 * \note Cores will sleep relatively quickly again, so it's important to issue
346 * the real detection code directly after this routine.
349 hardwareTopologyPrepareDetection()
351 #if defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_CONF) && \
352 (defined(THREAD_PTHREADS) || defined(THREAD_WINDOWS))
354 // Modify this conditional when/if x86 or PowerPC starts to sleep some cores
355 if (c_architecture != Architecture::X86 &&
356 c_architecture != Architecture::PowerPC)
358 int countConfigured = sysconf(_SC_NPROCESSORS_CONF);
359 std::vector<std::thread> workThreads(countConfigured);
361 for (auto &t : workThreads)
363 t = std::thread(spinUpCore);
366 for (auto &t : workThreads)
374 /*! \brief Sanity check hardware topology and print some notes to log
376 * \param mdlog Logger.
377 * \param hardwareTopology Reference to hardwareTopology object.
380 hardwareTopologyDoubleCheckDetection(const gmx::MDLogger gmx_unused &mdlog,
381 const gmx::HardwareTopology gmx_unused &hardwareTopology)
383 #if defined HAVE_SYSCONF && defined(_SC_NPROCESSORS_CONF)
384 if (hardwareTopology.supportLevel() < gmx::HardwareTopology::SupportLevel::LogicalProcessorCount)
389 int countFromDetection = hardwareTopology.machine().logicalProcessorCount;
390 int countConfigured = sysconf(_SC_NPROCESSORS_CONF);
392 /* BIOS, kernel or user actions can take physical processors
393 * offline. We already cater for the some of the cases inside the hardwareToplogy
394 * by trying to spin up cores just before we detect, but there could be other
395 * cases where it is worthwhile to hint that there might be more resources available.
397 if (countConfigured >= 0 && countConfigured != countFromDetection)
400 appendTextFormatted("Note: %d CPUs configured, but only %d were detected to be online.\n", countConfigured, countFromDetection);
402 if (c_architecture == Architecture::X86 &&
403 countConfigured == 2*countFromDetection)
406 appendText(" X86 Hyperthreading is likely disabled; enable it for better performance.");
408 // For PowerPC (likely Power8) it is possible to set SMT to either 2,4, or 8-way hardware threads.
409 // We only warn if it is completely disabled since default performance drops with SMT8.
410 if (c_architecture == Architecture::PowerPC &&
411 countConfigured == 8*countFromDetection)
414 appendText(" PowerPC SMT is likely disabled; enable SMT2/SMT4 for better performance.");
420 gmx_hw_info_t *gmx_detect_hardware(const gmx::MDLogger &mdlog,
421 const PhysicalNodeCommunicator &physicalNodeComm)
423 // By construction, only one thread ever runs hardware detection,
424 // but we may as well prevent issues arising if that would change.
425 // Taking the lock early ensures that exactly one thread can
426 // attempt to construct g_hardwareInfo.
427 lock_guard<Mutex> lock(g_hardwareInfoMutex);
429 // If we already have the information, just return a handle to it.
430 if (g_hardwareInfo != nullptr)
432 return g_hardwareInfo.get();
435 // Make the new hardwareInfo in a temporary.
436 hardwareTopologyPrepareDetection();
438 // TODO: We should also do CPU hardware detection only once on each
439 // physical node and broadcast it, instead of doing it on every MPI rank.
440 auto hardwareInfo = std::make_unique<gmx_hw_info_t>(std::make_unique<CpuInfo>(CpuInfo::detect()),
441 std::make_unique<HardwareTopology>(HardwareTopology::detect()));
443 // If we detected the topology on this system, double-check that it makes sense
444 if (hardwareInfo->hardwareTopology->isThisSystem())
446 hardwareTopologyDoubleCheckDetection(mdlog, *hardwareInfo->hardwareTopology);
449 // TODO: Get rid of this altogether.
450 hardwareInfo->nthreads_hw_avail = hardwareInfo->hardwareTopology->machine().logicalProcessorCount;
453 hardwareInfo->gpu_info.n_dev = 0;
454 hardwareInfo->gpu_info.n_dev_compatible = 0;
455 hardwareInfo->gpu_info.gpu_dev = nullptr;
457 gmx_detect_gpus(mdlog, physicalNodeComm, compat::make_not_null(hardwareInfo));
458 gmx_collect_hardware_mpi(*hardwareInfo->cpuInfo, physicalNodeComm, compat::make_not_null(hardwareInfo));
460 // Now that the temporary is fully constructed, swap it to become
462 g_hardwareInfo.swap(hardwareInfo);
464 return g_hardwareInfo.get();
467 bool compatibleGpusFound(const gmx_gpu_info_t &gpu_info)
469 return gpu_info.n_dev_compatible > 0;