mirror of
https://git.rwth-aachen.de/acs/public/villas/node/
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146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
/** Linux specific real-time optimizations
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*
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* @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
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* @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
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* @license GNU General Public License (version 3)
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*
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* VILLASnode
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*********************************************************************************/
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#include <sched.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <villas/config.h>
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#include <villas/utils.h>
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#include <villas/super_node.h>
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#include <villas/kernel/kernel.h>
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#include <villas/kernel/rt.h>
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int rt_init(int priority, int affinity)
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{
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info("Initialize real-time sub-system");
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{
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#ifdef __linux__
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int is_rt;
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/* Use FIFO scheduler with real time priority */
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is_rt = rt_is_preemptible();
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if (is_rt)
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warn("We recommend to use an PREEMPT_RT patched kernel!");
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if (priority)
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rt_set_priority(priority);
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else
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warn("You might want to use the 'priority' setting to increase VILLASnode's process priority");
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if (affinity)
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rt_set_affinity(affinity);
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else
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warn("You might want to use the 'affinity' setting to pin VILLASnode to dedicate CPU cores");
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rt_lock_memory();
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#else
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warn("This platform is not optimized for real-time execution");
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#endif
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}
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return 0;
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}
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#ifdef __linux__
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int rt_lock_memory()
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{
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int ret;
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#ifdef _POSIX_MEMLOCK
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ret = mlockall(MCL_CURRENT | MCL_FUTURE);
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if (ret)
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error("Failed to lock memory");
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#endif
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return 0;
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}
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int rt_set_affinity(int affinity)
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{
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char isolcpus[255];
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int is_isol, ret;
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/* Pin threads to CPUs by setting the affinity */
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cpu_set_t cset_pin, cset_isol, cset_non_isol;
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cpuset_from_integer(affinity, &cset_pin);
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is_isol = kernel_get_cmdline_param("isolcpus", isolcpus, sizeof(isolcpus));
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if (is_isol) {
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warn("You should reserve some cores for VILLASnode (see 'isolcpus')");
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CPU_ZERO(&cset_isol);
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}
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else {
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ret = cpulist_parse(isolcpus, &cset_isol, 0);
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if (ret)
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error("Invalid isolcpus cmdline parameter: %s", isolcpus);
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CPU_XOR(&cset_non_isol, &cset_isol, &cset_pin);
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if (CPU_COUNT(&cset_non_isol) > 0) {
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char isol[128], pin[128];
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cpulist_create(isol, sizeof(isol), &cset_isol);
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cpulist_create(pin, sizeof(pin), &cset_pin);
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warn("Affinity setting includes cores which are not isolated: affinity=%s isolcpus=%s", pin, isol);
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}
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}
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char list[128];
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cpulist_create(list, sizeof(list), &cset_pin);
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ret = sched_setaffinity(0, sizeof(cpu_set_t), &cset_pin);
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if (ret)
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serror("Failed to set CPU affinity to %s", list);
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debug(LOG_KERNEL | 3, "Set affinity to %s", list);
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return 0;
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}
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int rt_set_priority(int priority)
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{
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int ret;
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struct sched_param param = {
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.sched_priority = priority
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};
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ret = sched_setscheduler(0, SCHED_FIFO, ¶m);
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if (ret)
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serror("Failed to set real time priority");
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debug(LOG_KERNEL | 3, "Task priority set to %u", priority);
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return 0;
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}
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int rt_is_preemptible()
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{
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return access(SYSFS_PATH "/kernel/realtime", R_OK);
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}
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#endif /* __linux__ */
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