Merge pull request #22 from scheduler-tools/for-origin/broader-cpusets

rtapp: Add broader support for specifying cpusets

Author: Juri Lelli

doc/examples/tutorial/example8.json

@@ -0,0 +1,40 @@
+{
+	/*
+	 * Simple use case which creates a thread with 3 phases each running for
+	 * 1.5ms. In phase 1 the thread will be affined to CPU 0, in phase 2 it
+	 * will be affined to CPU 1 and in the third phase it will be affined to
+	 * CPUs 2 (inherit from "cpus" at task level).
+	 */
+	"tasks" : {
+		"thread0" : {
+			"cpus" : [2],
+			"phases" : {
+				"phase1" : {
+					"cpus" : [0],
+					"loop" : 1,
+					"run" : 1500
+				},
+				"phase2" : {
+					"cpus" : [1],
+					"loop" : 1,
+					"run" : 1500
+				},
+				"phase3" : {
+					"loop" : 1,
+					"run" : 1500
+				}
+			}
+		}
+	},
+	"global" : {
+		"duration" : 2,
+		"calibration" : "CPU0",
+		"default_policy" : "SCHED_OTHER",
+		"pi_enabled" : false,
+		"lock_pages" : false,
+		"logdir" : "./",
+		"log_basename" : "rt-app1",
+		"ftrace" : true,
+		"gnuplot" : true
+	}
+}

doc/tutorial.txt

@@ -232,6 +232,43 @@ below are equals:
 	}
 }
 
+"cpus" can be specified at task level or phase level. As an example, below
+creates two threads. One thread will run with affinity of CPU 2 and 3. The
+second task will run first phase with affinity to CPU 0 and 1, second phase with
+affinity to CPU 2, and the third phase with affinity to CPU 4, 5, and 6 (it will
+inherit the affinity from the task level):
+
+"task" : {
+	"thread1" : {
+		"cpus" : [2,3],
+		"phases" : {
+			"phase1" : {
+				"run" : 10,
+				"sleep" : 10
+			}
+		}
+	}
+	"thread2" : {
+		"cpus" : [4,5,6],
+		"phases" : {
+			"phase1" : {
+				"cpus" : [0,1],
+				"run" : 10,
+				"sleep" : 10
+			}
+			"phase2" : {
+				"cpus" : [2],
+				"run" : 10,
+				"sleep" : 10
+			}
+			"phase3" : {
+				"run" : 10,
+				"sleep" : 10
+			}
+		}
+	}
+}
+
 * loop: Integer. Define the number of times the parent object must be run.
 The parent object can be a phase or a thread. For phase object, the loop
 defines the number of time the phase will be executed before starting the next

src/rt-app.c

@@ -474,6 +474,116 @@ shutdown(int sig)
 	exit(EXIT_SUCCESS);
 }
 
+static void create_cpuset_str(cpuset_data_t *cpu_data)
+{
+	unsigned int cpu_count = CPU_COUNT_S(cpu_data->cpusetsize,
+							cpu_data->cpuset);
+	unsigned int i;
+	unsigned int idx = 0;
+
+	/*
+	 * Assume we can go up to 9999 cpus. Each cpu would take up to 4 + 2
+	 * bytes (4 for the number and 2 for the comma and space). 2 bytes
+	 * for beginning bracket + space and 2 bytes for end bracket and space
+	 * and finally null-terminator.
+	 */
+	unsigned int size_needed = cpu_count * 6 + 2 + 2 + 1;
+
+	if (cpu_count > 9999) {
+		log_error("Too many cpus specified. Up to 9999 cpus supported");
+		exit(EXIT_FAILURE);
+	}
+
+	cpu_data->cpuset_str = malloc(size_needed);
+	strcpy(cpu_data->cpuset_str, "[ ");
+	idx += 2;
+
+	for (i = 0; i < 10000 && cpu_count; ++i) {
+		unsigned int n;
+
+		if (CPU_ISSET(i, cpu_data->cpuset)) {
+			--cpu_count;
+			if (size_needed <= (idx + 1)) {
+				log_error("Not enough memory for array");
+				exit(EXIT_FAILURE);
+			}
+			n = snprintf(&cpu_data->cpuset_str[idx],
+						size_needed - idx - 1, "%d", i);
+			if (n > 0) {
+				idx += n;
+			} else {
+				log_error("Error creating array");
+				exit(EXIT_FAILURE);
+			}
+			if (size_needed <= (idx + 1)) {
+				log_error("Not enough memory for array");
+				exit(EXIT_FAILURE);
+			}
+			if (cpu_count) {
+				strncat(cpu_data->cpuset_str, ", ",
+							size_needed - idx - 1);
+				idx += 2;
+			}
+		}
+	}
+	strncat(cpu_data->cpuset_str, " ]", size_needed - idx - 1);
+}
+
+static void set_thread_affinity(thread_data_t *data, cpuset_data_t *cpu_data)
+{
+	int ret;
+	cpuset_data_t *actual_cpu_data = &data->cpu_data;
+
+	if (data->def_cpu_data.cpuset == NULL) {
+		/* Get default affinity */
+		cpu_set_t cpuset;
+		unsigned int cpu_count;
+		unsigned int cpu = 0;
+
+		ret = pthread_getaffinity_np(pthread_self(),
+						    sizeof(cpu_set_t), &cpuset);
+		if (ret != 0) {
+			errno = ret;
+			perror("pthread_get_affinity");
+			exit(EXIT_FAILURE);
+		}
+		cpu_count = CPU_COUNT(&cpuset);
+		data->def_cpu_data.cpusetsize = CPU_ALLOC_SIZE(cpu_count);
+		data->def_cpu_data.cpuset = CPU_ALLOC(cpu_count);
+		memcpy(data->def_cpu_data.cpuset, &cpuset,
+						data->def_cpu_data.cpusetsize);
+		create_cpuset_str(&data->def_cpu_data);
+		data->curr_cpu_data = &data->def_cpu_data;
+	}
+
+	/*
+	 * Order of preference:
+	 * 1. Phase cpuset
+	 * 2. Task level cpuset
+	 * 3. Default cpuset
+	 */
+	if (cpu_data->cpuset != NULL)
+		actual_cpu_data = cpu_data;
+
+	if (actual_cpu_data->cpuset == NULL)
+		actual_cpu_data = &data->def_cpu_data;
+
+	if (!CPU_EQUAL(actual_cpu_data->cpuset, data->curr_cpu_data->cpuset))
+	{
+		log_debug("[%d] setting cpu affinity to CPU(s) %s", data->ind,
+			actual_cpu_data->cpuset_str);
+		ret = pthread_setaffinity_np(pthread_self(),
+						actual_cpu_data->cpusetsize,
+						actual_cpu_data->cpuset);
+		if (ret != 0) {
+			errno = ret;
+			perror("pthread_setaffinity_np");
+			exit(EXIT_FAILURE);
+		}
+		data->curr_cpu_data = actual_cpu_data;
+	}
+}
+
 void *thread_body(void *arg)
 {
 	thread_data_t *data = (thread_data_t*) arg;
@@ -501,20 +611,6 @@ void *thread_body(void *arg)
 	/* Get the 1st phase's data */
 	pdata = &data->phases[0];
 
-	/* Set thread affinity */
-	if (data->cpuset != NULL)
-	{
-		log_notice("[%d] setting cpu affinity to CPU(s) %s", data->ind,
-			 data->cpuset_str);
-		ret = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t),
-						data->cpuset);
-		if (ret < 0) {
-			errno = ret;
-			perror("pthread_setaffinity_np");
-			exit(EXIT_FAILURE);
-		}
-	}
-
 	/* Set scheduling policy and print pretty info on stdout */
 	log_notice("[%d] Using %s policy with priority %d", data->ind, data->sched_policy_descr, data->sched_prio);
 	switch (data->sched_policy)
@@ -662,6 +758,8 @@ void *thread_body(void *arg)
 	while (continue_running && (i != data->loop)) {
 		struct timespec t_diff, t_rel_start;
 
+		set_thread_affinity(data, &pdata->cpu_data);
+
 		if (opts.ftrace)
 			log_ftrace(ft_data.marker_fd, "[%d] begins loop %d phase %d step %d", data->ind, i, j, loop);
 		log_debug("[%d] begins loop %d phase %d step %d", data->ind, i, j, loop);;

src/rt-app_parse_config.c

@@ -648,6 +648,41 @@ obj_is_event(char *name)
     return 0;
 }
 
+static void parse_cpuset_data(struct json_object *obj, cpuset_data_t *data)
+{
+	struct json_object *cpuset_obj, *cpu;
+	unsigned int max_cpu = sysconf(_SC_NPROCESSORS_CONF) - 1;
+
+	/* cpuset */
+	cpuset_obj = get_in_object(obj, "cpus", TRUE);
+	if (cpuset_obj) {
+		unsigned int i;
+		unsigned int cpu_idx;
+
+		assure_type_is(cpuset_obj, obj, "cpus", json_type_array);
+		data->cpuset_str = strdup(json_object_to_json_string(cpuset_obj));
+		data->cpusetsize = sizeof(cpu_set_t);
+		data->cpuset = malloc(data->cpusetsize);
+		CPU_ZERO(data->cpuset);
+		for (i = 0; i < json_object_array_length(cpuset_obj); i++) {
+			cpu = json_object_array_get_idx(cpuset_obj, i);
+			cpu_idx = json_object_get_int(cpu);
+			if (cpu_idx > max_cpu) {
+				log_critical(PIN2 "Invalid cpu %d in cpuset %s", cpu_idx, data->cpuset_str);
+				free(data->cpuset);
+				free(data->cpuset_str);
+				exit(EXIT_INV_CONFIG);
+			}
+			CPU_SET(cpu_idx, data->cpuset);
+		}
+	} else {
+		data->cpuset_str = strdup("-");
+		data->cpuset = NULL;
+		data->cpusetsize = 0;
+	}
+	log_info(PIN "key: cpus %s", data->cpuset_str);
+}
+
 static void
 parse_thread_phase_data(struct json_object *obj,
 		  phase_data_t *data, rtapp_options_t *opts, long tag)
@@ -681,6 +716,7 @@ parse_thread_phase_data(struct json_object *obj,
 			i++;
 		}
 	}
+	parse_cpuset_data(obj, &data->cpu_data);
 }
 
 static void
@@ -689,8 +725,8 @@ parse_thread_data(char *name, struct json_object *obj, int index,
 {
 	char *policy;
 	char def_policy[RTAPP_POLICY_DESCR_LENGTH];
-	struct json_object *cpuset_obj, *phases_obj, *cpu, *resources, *locks;
-	int i, cpu_idx, prior_def;
+	struct json_object *phases_obj, *resources;
+	int prior_def;
 
 	log_info(PFX "Parsing thread %s [%d]", name, index);
 
@@ -699,8 +735,11 @@ parse_thread_data(char *name, struct json_object *obj, int index,
 	data->ind = index;
 	data->name = strdup(name);
 	data->lock_pages = opts->lock_pages;
-	data->cpuset = NULL;
-	data->cpuset_str = NULL;
+	data->cpu_data.cpuset = NULL;
+	data->cpu_data.cpuset_str = NULL;
+	data->curr_cpu_data = NULL;
+	data->def_cpu_data.cpuset = NULL;
+	data->def_cpu_data.cpuset_str = NULL;
 
 	/* policy */
 	policy_to_string(opts->policy, def_policy);
@@ -734,22 +773,7 @@ parse_thread_data(char *name, struct json_object *obj, int index,
 		data->deadline = get_int_value_from(obj, "deadline", TRUE, data->period);
 
 	/* cpuset */
-	cpuset_obj = get_in_object(obj, "cpus", TRUE);
-	if (cpuset_obj) {
-		assure_type_is(cpuset_obj, obj, "cpus", json_type_array);
-		data->cpuset_str = strdup(json_object_to_json_string(cpuset_obj));
-		data->cpuset = malloc(sizeof(cpu_set_t));
-		CPU_ZERO(data->cpuset);
-		for (i = 0; i < json_object_array_length(cpuset_obj); i++) {
-			cpu = json_object_array_get_idx(cpuset_obj, i);
-			cpu_idx = json_object_get_int(cpu);
-			CPU_SET(cpu_idx, data->cpuset);
-		}
-	} else {
-		data->cpuset_str = strdup("-");
-		data->cpuset = NULL;
-	}
-	log_info(PIN "key: cpus %s", data->cpuset_str);
+	parse_cpuset_data(obj, &data->cpu_data);
 
 	/* initial delay */
 	data->delay = get_int_value_from(obj, "delay", TRUE, 0);

src/rt-app_types.h

@@ -141,10 +141,17 @@ typedef struct _event_data_t {
 	int count;
 } event_data_t;
 
+typedef struct _cpuset_data_t {
+	cpu_set_t *cpuset;
+	char *cpuset_str;
+	size_t cpusetsize;
+} cpuset_data_t;
+
 typedef struct _phase_data_t {
 	int loop;
 	event_data_t *events;
 	int nbevents;
+	cpuset_data_t cpu_data;
 } phase_data_t;
 
 typedef struct _thread_data_t {
@@ -153,8 +160,9 @@ typedef struct _thread_data_t {
 	int lock_pages;
 	int duration;
 	rtapp_resource_t **resources;
-	cpu_set_t *cpuset;
-	char *cpuset_str;
+	cpuset_data_t cpu_data; /* cpu set information */
+	cpuset_data_t *curr_cpu_data; /* Current cpu set being used */
+	cpuset_data_t def_cpu_data; /* Default cpu set for task */
 
 	unsigned long runtime, deadline, period;