X-Git-Url: http://git.rrze.uni-erlangen.de/gitweb/?p=LbmBenchmarkKernelsPublic.git;a=blobdiff_plain;f=src%2FPinning.c;fp=src%2FPinning.c;h=0cf70eafbddd61e8aa2968f544a1d1f499ad6eb0;hp=0000000000000000000000000000000000000000;hb=109880839321408644c94a34eb31208460b9f46d;hpb=42cf91486fb5c1ad178b3d21935a1be563e5fa39
diff --git a/src/Pinning.c b/src/Pinning.c
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+// --------------------------------------------------------------------------
+//
+// Copyright
+// Markus Wittmann, 2016-2017
+// RRZE, University of Erlangen-Nuremberg, Germany
+// markus.wittmann -at- fau.de or hpc -at- rrze.fau.de
+//
+// Viktor Haag, 2016
+// LSS, University of Erlangen-Nuremberg, Germany
+//
+// This file is part of the Lattice Boltzmann Benchmark Kernels (LbmBenchKernels).
+//
+// LbmBenchKernels is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// LbmBenchKernels is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with LbmBenchKernels. If not, see .
+//
+// --------------------------------------------------------------------------
+#ifndef _GNU_SOURCE
+ #define _GNU_SOURCE
+#endif
+#include
+#include
+
+
+#include "Base.h"
+#include "Pinning.h"
+
+
+
+
+// -----------------------------------------------------------------------
+//
+// Binds the calling thread to specified core.
+//
+// Return value: 0 = success, else error.
+//
+// -----------------------------------------------------------------------
+
+int PinCurrentThreadToCore(int coreNumber)
+{
+ int error = 0;
+
+ cpu_set_t cpu_set;
+ CPU_ZERO(&cpu_set);
+ CPU_SET(coreNumber, &cpu_set);
+
+ error = sched_setaffinity((pid_t)0, sizeof(cpu_set_t), &cpu_set);
+
+ if (error != 0) {
+ Error("pinning thread to core %d failed (%d): %s\n",
+ coreNumber, error, strerror(error));
+ }
+
+ return error;
+}
+
+
+// -----------------------------------------------------------------------
+//
+// Binds the calling thread to specified core by a cpu list specified
+// in the given environment variable.
+//
+// Return value: 0 = success, else error.
+//
+// -----------------------------------------------------------------------
+
+int PinCurrentThreadByEnvVar(const char * envVarName,
+ int mpiRank, int nodeRank, int threadNumber)
+{
+ const char * envVarValue;
+ int core;
+
+ envVarValue = getenv(envVarName);
+
+ if (envVarValue == NULL) {
+ if (mpiRank == 0) {
+ Print("skip pinning: env var %s not set\n", envVarName);
+ }
+
+ return 0;
+ }
+
+ core = PinParseCpuList(envVarValue, mpiRank, nodeRank, threadNumber);
+
+ if (core < 0) {
+ return core;
+ }
+
+ return PinCurrentThreadToCore(core);
+}
+
+
+// -----------------------------------------------------------------------
+//
+// Binds the calling thread to a core specified in the CPU list.
+//
+// Return value: 0 = success, else error.
+//
+// -----------------------------------------------------------------------
+
+int PinCurrentThreadByCpuList(const char * cpuList,
+ int mpiRank, int nodeRank, int threadNumber)
+{
+ int core;
+
+ if (cpuList == NULL) {
+ if (mpiRank == 0) {
+ printf("ERROR: cpu list is NULL.\n");
+ }
+
+ exit(1);
+ }
+
+ core = PinParseCpuList(cpuList, mpiRank, nodeRank, threadNumber);
+
+ if (core < 0) {
+ return core;
+ }
+
+ return PinCurrentThreadToCore(core);
+}
+
+
+// -----------------------------------------------------------------------
+//
+// Parses the provided cpu list and returns the core number for the
+// specified MPI rank, local rank, and thread.
+//
+// The cpu list has for example a format of: 0,1,2 or 0,1,2_3,4,5
+//
+// Blocks (0,1,2 or 3,4,5) separated by "_" specify pinning inside a
+// node rank. The first block maps to node rank 1, the second to node
+// rank 2, etc.
+//
+// Inside a block the core numbers specify where the threads should
+// be pinned to. They are separated by "," and the first number maps
+// to the first core, the second number to the second core, etc.
+//
+// For example: 0,2,4_6,8,10
+//
+// Node rank 0 thread 0 pinned to core 0
+// 0 1 2
+// 0 2 4
+// 1 0 6
+// 1 1 8
+// 1 2 10
+//
+// -----------------------------------------------------------------------
+
+int PinParseCpuList(const char * cpuList,
+ int mpiRank, int nodeRank, int threadNumber)
+{
+ int cpu = -1;
+
+ if (cpuList == NULL) {
+ return -1;
+ }
+
+ const char * c = cpuList;
+
+ // Ensure only valid characters are in the cpu list.
+ // Cpu list is in the format of "0,1,2_3,4,5".
+ while (((*c >= '0' && *c <= '9') || *c == ',' || *c == '_')) {
+ ++c;
+ }
+
+ if (*c != 0x00) {
+ // Invalid character detected.
+ return -2;
+ }
+
+ c = cpuList;
+
+ int i = 0;
+
+ // Move variable c after the "nodeRank"th "_" in the cpu list.
+ while (i < nodeRank && *c != 0x00) {
+ if (*c == '_') ++i;
+ ++c;
+ }
+
+ if (i != nodeRank || *c < '0' || *c > '9') {
+ // Cpu list for this node rank not found.
+ return -3;
+ }
+
+ // Now find the core for the specified thread.
+
+ int t = 0;
+
+ while (t < threadNumber && *c != 0x00) {
+ if (*c == ',') {
+ ++t;
+ }
+ else if (*c == '_') {
+ // Unexpected character at this position.
+ break;
+ }
+
+ ++c;
+ }
+
+ if (t != threadNumber || *c < '0' || *c > '9') {
+ // Cpu for this threadNumber not found.
+ return -4;
+ }
+
+ cpu = atoi(c);
+
+ return cpu;
+}
+
+
+
+// -----------------------------------------------------------------------
+//
+// Returns the first core from the calling thread's affinity set.
+//
+// On error a value < 0 is returned.
+//
+// -----------------------------------------------------------------------
+
+int PinCurrentCore()
+{
+ int core = -1;
+ int err;
+
+ cpu_set_t cpu_set;
+ CPU_ZERO(&cpu_set);
+
+ err = sched_getaffinity((pid_t)0, sizeof(cpu_set_t), &cpu_set);
+
+ // constant CPU_SETSIZE is one larger than the maximum CPU
+ // number that can be stored in a CPU set
+ for (int i = 0; i < CPU_SETSIZE; ++i) {
+ if (CPU_ISSET(i, &cpu_set)) {
+ core = i;
+ break;
+ }
+ }
+
+ if (err != 0) {
+ Error("getting thread affinty failed (%d): %s\n", err, strerror(err));
+ return -1;
+ }
+
+ return core;
+}
+
+
+
+// -----------------------------------------------------------------------
+//
+// Returns the all cores from the calling thread's affinity set.
+//
+// On error a value < 0 is returned.
+//
+// -----------------------------------------------------------------------
+
+typedef cpu_set_t CpuSet;
+
+
+static CpuSet PinCurrentCores()
+{
+ CpuSet cpuSet;
+ int err;
+
+ cpu_set_t cpu_set;
+ CPU_ZERO(&cpu_set);
+
+ err = sched_getaffinity((pid_t)0, sizeof(cpu_set_t), &cpu_set);
+
+ cpuSet = cpu_set;
+
+ if (err != 0) {
+ Error("getting thread affinty failed (%d): %s\n", err, strerror(err));
+ return cpuSet;
+ }
+
+ return cpuSet;
+}
+
+static char * CpuSetToString(cpu_set_t * cpu_set)
+{
+ int previousSetCore = -2;
+ int rangeBeginCore = -2;
+
+ char * buffer1 = (char *)malloc(1024);
+ Assert(buffer1 != NULL);
+ char * buffer2 = (char *)malloc(1024);
+ Assert(buffer2 != NULL);
+
+ buffer1[0] = 0x00;
+ buffer2[0] = 0x00;
+
+ char * buffer = buffer1;
+ char * bufferOld = buffer2;
+
+ const char * empty = "";
+ const char * realComma = ",";
+ const char * comma = empty;
+
+ // TODO: use snprintf
+ // TODO: increase allocated buffer if necessary
+
+ for (int i = 0; i < CPU_SETSIZE; ++i) {
+ if (!CPU_ISSET(i, cpu_set)) {
+ continue;
+ }
+
+ if (i == previousSetCore + 1) {
+ previousSetCore = i;
+ continue;
+ }
+
+ // Now we reached the end of a range.
+ // The range can also consist of only one core.
+ // Be aware, that this core is not part of the range.
+
+ // TODO: this code is repeated below -> use it only once
+ if (rangeBeginCore >= 0 && previousSetCore >= 0) {
+ char * tmp;
+
+ tmp = buffer;
+ buffer = bufferOld;
+ bufferOld = tmp;
+
+ if (rangeBeginCore < previousSetCore) {
+ sprintf(buffer, "%s%s%d-%d", bufferOld, comma, rangeBeginCore, previousSetCore);
+ }
+ else {
+ sprintf(buffer, "%s%s%d", bufferOld, comma, previousSetCore);
+ }
+
+ comma = realComma;
+ }
+
+ // With this core a new range begins.
+ rangeBeginCore = i;
+ previousSetCore = i;
+ }
+
+ if (rangeBeginCore >= 0 && previousSetCore >= 0) {
+ char * tmp;
+
+ tmp = buffer;
+ buffer = bufferOld;
+ bufferOld = tmp;
+
+ if (rangeBeginCore < previousSetCore) {
+ sprintf(buffer, "%s%s%d-%d", bufferOld, comma, rangeBeginCore, previousSetCore);
+ }
+ else {
+ sprintf(buffer, "%s%s%d", bufferOld, comma, previousSetCore);
+ }
+ }
+
+ free(bufferOld); bufferOld = NULL;
+
+ return buffer;
+}
+
+char * PinCpuListAsString()
+{
+ CpuSet cpuSet = PinCurrentCores();
+
+ return CpuSetToString(&cpuSet);
+}
+
+#ifdef TEST
+
+int main(int argc, char * argv[])
+{
+ char * cpuList = PinCpuListAsString();
+
+ printf("pinned to cores: %s\n", cpuList);
+
+ free(cpuList); cpuList = NULL;
+
+ return 0;
+}
+
+#endif // TEST
+