#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
-#if defined(HAVE_SCHED_H) && (defined(HAVE_SCHED_GETAFFINITY) || defined(HAVE_SCHED_SETAFFINITY))
+#if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_GETAFFINITY)
#define _GNU_SOURCE
#include <sched.h>
#include <sys/syscall.h>
#include "macros.h"
#include "gmx_omp.h"
+#include "thread_mpi/threads.h"
+
#ifdef GMX_LIB_MPI
#include <mpi.h>
#endif
}
#endif
-#ifdef GMX_OPENMP /* TODO: actually we could do this even without OpenMP?! */
-#ifdef HAVE_SCHED_SETAFFINITY
+#ifndef __APPLE__
+ /* If the tMPI thread affinity setting is not supported encourage the user
+ * to report it as it's either a bug or an exotic platform which we might
+ * want to support. */
+ if (tMPI_Thread_setaffinity_support() != TMPI_SETAFFINITY_SUPPORT_YES)
+ {
+ md_print_warn(NULL, fplog,
+ "Can not set thread affinities on the current plarform. On NUMA systems this\n"
+ "can cause performance degradation. If you think your platform should support\n"
+ "setting affinities, contact the GROMACS developers.");
+ return;
+ }
+#endif /* __APPLE__ */
+
if (hw_opt->bThreadPinning)
{
- int thread, nthread_local, nthread_node, nthread_hw_max, nphyscore;
+ int nth_affinity_set, thread_id_node, thread_id,
+ nthread_local, nthread_node, nthread_hw_max, nphyscore;
int offset;
char *env;
}
/* map the current process to cores */
- thread = 0;
+ thread_id_node = 0;
nthread_node = nthread_local;
#ifdef GMX_MPI
if (PAR(cr) || MULTISIM(cr))
/* We need to determine a scan of the thread counts in this
* compute node.
*/
+ int process_index;
MPI_Comm comm_intra;
- MPI_Comm_split(MPI_COMM_WORLD,gmx_hostname_num(),cr->nodeid_intra,
+ process_index = cr->nodeid_intra;
+ if (MULTISIM(cr))
+ {
+ /* To simplify the code, we shift process indices by nnodes.
+ * There might be far less processes, but that doesn't matter.
+ */
+ process_index += cr->ms->sim*cr->nnodes;
+ }
+ MPI_Comm_split(MPI_COMM_WORLD,gmx_hostname_num(),process_index,
&comm_intra);
- MPI_Scan(&nthread_local,&thread,1,MPI_INT,MPI_SUM,comm_intra);
+ MPI_Scan(&nthread_local,&thread_id_node,1,MPI_INT,MPI_SUM,comm_intra);
/* MPI_Scan is inclusive, but here we need exclusive */
- thread -= nthread_local;
+ thread_id_node -= nthread_local;
/* Get the total number of threads on this physical node */
MPI_Allreduce(&nthread_local,&nthread_node,1,MPI_INT,MPI_SUM,comm_intra);
MPI_Comm_free(&comm_intra);
}
}
- /* set the per-thread affinity */
-#pragma omp parallel firstprivate(thread) num_threads(nthread_local)
+ /* Set the per-thread affinity. In order to be able to check the success
+ * of affinity settings, we will set nth_affinity_set to 1 on threads
+ * where the affinity setting succeded and to 0 where it failed.
+ * Reducing these 0/1 values over the threads will give the total number
+ * of threads on which we succeeded.
+ */
+ nth_affinity_set = 0;
+#pragma omp parallel firstprivate(thread_id_node) num_threads(nthread_local) \
+ reduction(+:nth_affinity_set)
{
- cpu_set_t mask;
- int core;
+ int core;
+ gmx_bool setaffinity_ret;
- CPU_ZERO(&mask);
- thread += gmx_omp_get_thread_num();
+ thread_id = gmx_omp_get_thread_num();
+ thread_id_node += thread_id;
if (nphyscore <= 0)
{
- core = offset + thread;
+ core = offset + thread_id_node;
}
else
{
/* Lock pairs of threads to the same hyperthreaded core */
- core = offset + thread/2 + (thread % 2)*nphyscore;
+ core = offset + thread_id_node/2 + (thread_id_node % 2)*nphyscore;
+ }
+
+ setaffinity_ret = tMPI_Thread_setaffinity_single(tMPI_Thread_self(), core);
+
+ /* store the per-thread success-values of the setaffinity */
+ nth_affinity_set = (setaffinity_ret == 0);
+
+ if (debug)
+ {
+ fprintf(debug, "On node %d, thread %d the affinity setting returned %d\n",
+ cr->nodeid, gmx_omp_get_thread_num(), setaffinity_ret);
+ }
+ }
+
+ if (nth_affinity_set > nthread_local)
+ {
+ char msg[STRLEN];
+
+ sprintf(msg, "Looks like we have set affinity for more threads than "
+ "we have (%d > %d)!\n", nth_affinity_set, nthread_local);
+ gmx_incons(msg);
+ }
+ else
+ {
+ /* check if some threads failed to set their affinities */
+ if (nth_affinity_set != nthread_local)
+ {
+ char sbuf[STRLEN];
+ sbuf[0] = '\0';
+#ifdef GMX_MPI
+#ifdef GMX_THREAD_MPI
+ sprintf(sbuf, "In thread-MPI thread #%d", cr->nodeid);
+#else /* GMX_LIB_MPI */
+#endif
+ sprintf(sbuf, "In MPI process #%d", cr->nodeid);
+#endif /* GMX_MPI */
+ md_print_warn(NULL, fplog,
+ "%s%d/%d thread%s failed to set their affinities. "
+ "This can cause performance degradation!",
+ sbuf, nthread_local - nth_affinity_set, nthread_local,
+ (nthread_local - nth_affinity_set) > 1 ? "s" : "");
}
- CPU_SET(core, &mask);
- sched_setaffinity((pid_t) syscall (SYS_gettid), sizeof(cpu_set_t), &mask);
}
}
-#endif /* HAVE_SCHED_SETAFFINITY */
-#endif /* GMX_OPENMP */
}
biod.pnpi.spb.ru / alexxy / gromacs.git / blobdiff