| /* |
| * Copyright (c) 2018 Google, Inc. |
| * |
| * SPDX-License-Identifier: GPL-2.0-or-later |
| * |
| * A DL task and a CFS task are created and affined to the same CPU. The CFS |
| * task is a CPU hog. The latency to switch to the DL task (which should preempt |
| * the CFS task immediately) is checked. |
| */ |
| |
| #define _GNU_SOURCE |
| #include <errno.h> |
| #include <pthread.h> |
| #include <sched.h> |
| #include <semaphore.h> |
| #include <time.h> |
| |
| #include "tst_test.h" |
| #include "tst_safe_file_ops.h" |
| #include "tst_safe_pthread.h" |
| |
| #include "lapi/syscalls.h" |
| #include "lapi/sched.h" |
| #include "trace_parse.h" |
| #include "util.h" |
| |
| #define TRACE_EVENTS "sched_wakeup sched_switch" |
| |
| #define MAX_EXEC_LATENCY_US 100 |
| |
| static int dl_task_tid; |
| static sem_t sem; |
| |
| /* |
| * It is not possible to restrict CPU affinity on SCHED_DEADLINE tasks, so we do |
| * not force the CFS and DL tasks to be on the same CPU in this test. CPUsets |
| * can be used to do this, perhaps implement that later. |
| */ |
| |
| static void *dl_fn(void *arg LTP_ATTRIBUTE_UNUSED) |
| { |
| struct sched_attr attr; |
| |
| attr.size = sizeof(attr); |
| attr.sched_flags = 0; |
| attr.sched_nice = 0; |
| attr.sched_priority = 0; |
| |
| attr.sched_policy = SCHED_DEADLINE; |
| attr.sched_runtime = 10000000; |
| attr.sched_period = 30000000; |
| attr.sched_deadline = 30000000; |
| |
| ERROR_CHECK(sched_setattr(0, &attr, 0)); |
| |
| dl_task_tid = gettid(); |
| sem_wait(&sem); |
| return NULL; |
| } |
| |
| static void *cfs_fn(void *arg LTP_ATTRIBUTE_UNUSED) |
| { |
| usleep(5000); |
| tracefs_write("trace_marker", "WAKING"); |
| sem_post(&sem); |
| |
| burn(USEC_PER_SEC, 0); |
| return NULL; |
| } |
| |
| static int parse_results(void) |
| { |
| int i; |
| unsigned long long dl_wakeup_ts_us = 0; |
| unsigned long long dl_exec_ts_us = 0; |
| unsigned long dl_exec_latency_us; |
| |
| for (i = 0; i < num_trace_records; i++) { |
| if (trace[i].event_type == TRACE_RECORD_SCHED_WAKEUP) { |
| struct trace_sched_wakeup *t = trace[i].event_data; |
| if (t->pid != dl_task_tid) |
| continue; |
| dl_wakeup_ts_us = TS_TO_USEC(trace[i].ts); |
| continue; |
| } |
| if (dl_wakeup_ts_us && |
| trace[i].event_type == TRACE_RECORD_SCHED_SWITCH) { |
| struct trace_sched_switch *t = trace[i].event_data; |
| if (t->next_pid != dl_task_tid) |
| continue; |
| if (!dl_wakeup_ts_us) { |
| printf("DL task woke without being woken!\n"); |
| return -1; |
| } |
| dl_exec_ts_us = TS_TO_USEC(trace[i].ts); |
| break; |
| } |
| } |
| if (!dl_wakeup_ts_us || !dl_exec_ts_us) { |
| printf("DL task either wasn't woken or didn't wake up.\n"); |
| return -1; |
| } |
| dl_exec_latency_us = dl_exec_ts_us - dl_wakeup_ts_us; |
| printf("DL exec latency: %ld usec\n", dl_exec_latency_us); |
| return (dl_exec_latency_us > MAX_EXEC_LATENCY_US); |
| } |
| |
| static void run(void) |
| { |
| pthread_t cfs_thread; |
| pthread_t dl_thread; |
| pthread_attr_t cfs_thread_attrs; |
| pthread_attr_t dl_thread_attrs; |
| struct sched_param cfs_thread_sched_params; |
| struct sched_param dl_thread_sched_params; |
| |
| ERROR_CHECK(pthread_attr_init(&cfs_thread_attrs)); |
| ERROR_CHECK(pthread_attr_setinheritsched(&cfs_thread_attrs, |
| PTHREAD_EXPLICIT_SCHED)); |
| ERROR_CHECK(pthread_attr_setschedpolicy(&cfs_thread_attrs, |
| SCHED_OTHER)); |
| cfs_thread_sched_params.sched_priority = 0; |
| ERROR_CHECK(pthread_attr_setschedparam(&cfs_thread_attrs, |
| &cfs_thread_sched_params)); |
| |
| ERROR_CHECK(pthread_attr_init(&dl_thread_attrs)); |
| ERROR_CHECK(pthread_attr_setinheritsched(&dl_thread_attrs, |
| PTHREAD_EXPLICIT_SCHED)); |
| ERROR_CHECK(pthread_attr_setschedpolicy(&dl_thread_attrs, |
| SCHED_FIFO)); |
| dl_thread_sched_params.sched_priority = 80; |
| ERROR_CHECK(pthread_attr_setschedparam(&dl_thread_attrs, |
| &dl_thread_sched_params)); |
| |
| sem_init(&sem, 0, 0); |
| |
| /* configure and enable tracing */ |
| tracefs_write("tracing_on", "0"); |
| tracefs_write("buffer_size_kb", "16384"); |
| tracefs_write("set_event", TRACE_EVENTS); |
| tracefs_write("trace", "\n"); |
| tracefs_write("tracing_on", "1"); |
| |
| SAFE_PTHREAD_CREATE(&cfs_thread, &cfs_thread_attrs, cfs_fn, NULL); |
| SAFE_PTHREAD_CREATE(&dl_thread, &dl_thread_attrs, dl_fn, NULL); |
| SAFE_PTHREAD_JOIN(cfs_thread, NULL); |
| SAFE_PTHREAD_JOIN(dl_thread, NULL); |
| |
| /* disable tracing */ |
| tracefs_write("tracing_on", "0"); |
| LOAD_TRACE(); |
| |
| if (parse_results()) |
| tst_res(TFAIL, "DL task did not execute within expected " |
| "latency of %d usec.\n", MAX_EXEC_LATENCY_US); |
| else |
| tst_res(TPASS, "DL task executed within expected latency " |
| "of %d usec.\n", MAX_EXEC_LATENCY_US); |
| } |
| |
| static struct tst_test test = { |
| .test_all = run, |
| .setup = trace_setup, |
| .cleanup = trace_cleanup, |
| }; |