cavs: budgeting for EDF tasks

Kconfig

@@ -127,6 +127,13 @@ config INTERRUPT_LEVEL_5
 
 rsource "src/Kconfig"
 
+config IDC_TASK_BUDGET
+	int "Cycles budget for IDC task"
+	depends on SMP
+	default 8000
+	help
+	  Cycles budget for IDC task per systick (see config SYSTICK).
+
 choice
 	prompt "Optimization"
 	default OPTIMIZE_FOR_PERFORMANCE

src/drivers/intel/Kconfig

@@ -47,6 +47,13 @@ config INTEL_DMIC
 	  Select this to enable Intel DMIC driver. The DMIC driver provides
 	  as DAI the SoC direct attach digital microphones interface.
 
+config INTEL_CAVS_IPC_TASK_BUDGET
+	int "Intel cycles budget for IPC task"
+	depends on CAVS
+	default 8000
+	help
+	  Cycles budget for IPC task per systick (see config SYSTICK).
+
 if INTEL_DMIC
 
 choice

src/drivers/intel/cavs/ipc.c

@@ -295,8 +295,10 @@ int platform_ipc_init(struct ipc *ipc)
 	ipc_set_drvdata(ipc, NULL);
 
 	/* schedule */
-	schedule_task_init_edf(&ipc->ipc_task, SOF_UUID(ipc_task_uuid),
-			       &ipc_task_ops, ipc, 0, 0);
+	schedule_task_init_edf_with_budget(&ipc->ipc_task,
+					   SOF_UUID(ipc_task_uuid),
+					   &ipc_task_ops, ipc, 0, 0,
+					   CONFIG_INTEL_CAVS_IPC_TASK_BUDGET);
 
 	/* configure interrupt */
 	irq = interrupt_get_irq(PLATFORM_IPC_INTERRUPT,

src/idc/idc.c

@@ -325,8 +325,10 @@ int idc_init(void)
 	(*idc)->payload = cache_to_uncache((struct idc_payload *)payload);
 
 	/* process task */
-	schedule_task_init_edf(&(*idc)->idc_task, SOF_UUID(idc_cmd_task_uuid),
-			       &ops, *idc, cpu_get_id(), 0);
+	schedule_task_init_edf_with_budget(&(*idc)->idc_task,
+					   SOF_UUID(idc_cmd_task_uuid),
+					   &ops, *idc, cpu_get_id(), 0,
+					   CONFIG_IDC_TASK_BUDGET);
 
 	return platform_idc_init();
 }

src/include/sof/drivers/timer.h

@@ -9,6 +9,7 @@
 #define __SOF_DRIVERS_TIMER_H__
 
 #include <arch/drivers/timer.h>
+#include <sof/lib/cpu.h>
 #include <sof/sof.h>
 #include <stdint.h>
 
@@ -33,7 +34,7 @@ static inline struct timer *timer_get(void)
 
 static inline struct timer *cpu_timer_get(void)
 {
-	return sof_get()->cpu_timer;
+	return &(sof_get()->cpu_timers[cpu_get_id()]);
 }
 
 static inline int64_t timer_set(struct timer *timer, uint64_t ticks)

src/include/sof/schedule/edf_schedule.h

@@ -12,6 +12,7 @@
 #include <sof/trace/trace.h>
 #include <user/trace.h>
 #include <stdint.h>
+#include <stdbool.h>
 
 #define edf_sch_set_pdata(task, data) \
 	(task->priv_data = data)
@@ -20,6 +21,10 @@
 
 struct edf_task_pdata {
 	void *ctx;
+	uint32_t budget;	/**< cycles per systick */
+	uint64_t last_systick;	/**< last systick in which budget
+				  *  was granted to task
+				  */
 };
 
 int scheduler_init_edf(void);
@@ -28,4 +33,9 @@ int schedule_task_init_edf(struct task *task, uint32_t uid,
 			   const struct task_ops *ops,
 			   void *data, uint16_t core, uint32_t flags);
 
+int schedule_task_init_edf_with_budget(struct task *task, uint32_t uid,
+				       const struct task_ops *ops,
+				       void *data, uint16_t core,
+				       uint32_t flags, uint32_t cycles_budget);
+
 #endif /* __SOF_SCHEDULE_EDF_SCHEDULE_H__ */

src/include/sof/sof.h

@@ -60,8 +60,8 @@ struct sof {
 	/* default platform timer */
 	struct timer *platform_timer;
 
-	/* cpu (arch) timer */
-	struct timer *cpu_timer;
+	/* cpu (arch) timers - 1 per core */
+	struct timer *cpu_timers;
 
 	/* timer domain for driving timer LL scheduler */
 	struct ll_schedule_domain *platform_timer_domain;

src/platform/baytrail/platform.c

@@ -199,7 +199,7 @@ int platform_init(struct sof *sof)
 	int ret;
 
 	sof->platform_timer = &timer;
-	sof->cpu_timer = &timer;
+	sof->cpu_timers = &timer;
 
 	/* clear mailbox for early trace and debug */
 	trace_point(TRACE_BOOT_PLATFORM_MBOX);

src/platform/haswell/platform.c

@@ -186,7 +186,7 @@ int platform_init(struct sof *sof)
 	int ret;
 
 	sof->platform_timer = &timer;
-	sof->cpu_timer = &timer;
+	sof->cpu_timers = &timer;
 
 	/* clear mailbox for early trace and debug */
 	trace_point(TRACE_BOOT_PLATFORM_MBOX);

src/platform/imx8/platform.c

@@ -168,7 +168,7 @@ int platform_init(struct sof *sof)
 	int ret;
 
 	sof->platform_timer = &timer;
-	sof->cpu_timer = &timer;
+	sof->cpu_timers = &timer;
 
 	platform_interrupt_init();
 	platform_clock_init(sof);

src/platform/imx8m/platform.c

@@ -167,7 +167,7 @@ int platform_init(struct sof *sof)
 	int ret;
 
 	sof->platform_timer = &timer;
-	sof->cpu_timer = &timer;
+	sof->cpu_timers = &timer;
 
 	platform_interrupt_init();
 	platform_clock_init(sof);

src/platform/intel/cavs/platform.c

@@ -265,10 +265,7 @@ SHARED_DATA struct timer timer = {
 	.irq_name = irq_name_level2,
 };
 
-SHARED_DATA struct timer arch_timer = {
-	.id = TIMER1, /* internal timer */
-	.irq = IRQ_NUM_TIMER2,
-};
+SHARED_DATA struct timer arch_timers[PLATFORM_CORE_COUNT];
 
 #if CONFIG_DW_SPI
 
@@ -363,7 +360,13 @@ int platform_init(struct sof *sof)
 	int i;
 
 	sof->platform_timer = cache_to_uncache(&timer);
-	sof->cpu_timer = cache_to_uncache(&arch_timer);
+	sof->cpu_timers = (struct timer *)cache_to_uncache(&arch_timers);
+
+	for (i = 0; i < PLATFORM_CORE_COUNT; i++)
+		sof->cpu_timers[i] = (struct timer) {
+			.id = TIMER1, /* internal timer */
+			.irq = IRQ_NUM_TIMER2,
+		};
 
 	/* Turn off memory for all unused cores */
 	for (i = 0; i < PLATFORM_CORE_COUNT; i++)

src/schedule/edf_schedule.c

@@ -55,6 +55,26 @@ static void schedule_edf_task_run(struct task *task, void *data)
 	}
 }
 
+static inline uint64_t edf_eval_task_deadline(struct task *task,
+					      uint64_t systick)
+{
+	struct edf_task_pdata *edf_pdata = edf_sch_get_pdata(task);
+
+	if (!edf_pdata->budget)
+		return task_get_deadline(task);
+
+	/* check if task was already executed in current systick */
+	if (edf_pdata->last_systick != systick) {
+		edf_pdata->last_systick = systick;
+		return task_get_deadline(task);
+	}
+
+	/* when there are no other tasks to run,
+	 * task can be executed even if it used systick's budget,
+	 */
+	return SOF_TASK_DEADLINE_ALMOST_IDLE;
+}
+
 static void edf_scheduler_run(void *data)
 {
 	struct edf_schedule_data *edf_sch = data;
@@ -64,9 +84,20 @@ static void edf_scheduler_run(void *data)
 	struct task *task;
 	uint64_t deadline;
 	uint32_t flags;
+	uint64_t systick;
 
 	tr_dbg(&edf_tr, "edf_scheduler_run()");
 
+	timer_disable(cpu_timer_get(), edf_sch, cpu_get_id());
+
+	/* budget is given per systick, for example if systick is configured
+	 * as 1ms and budget is 8000 cycles, then task will be able to use
+	 * up to 8MCPS (or more if there are no other tasks)
+	 */
+	systick = platform_timer_get(timer_get()) /
+		  (clock_ms_to_ticks(PLATFORM_DEFAULT_CLOCK, 1)
+		   * (CONFIG_SYSTICK_PERIOD / 1000));
+
 	irq_local_disable(flags);
 
 	/* find next task to run */
@@ -77,7 +108,7 @@ static void edf_scheduler_run(void *data)
 		    task->state != SOF_TASK_STATE_RUNNING)
 			continue;
 
-		deadline = task_get_deadline(task);
+		deadline = edf_eval_task_deadline(task, systick);
 
 		if (deadline == SOF_TASK_DEADLINE_NOW) {
 			/* task needs to be scheduled ASAP */
@@ -143,6 +174,15 @@ static int schedule_edf_task(void *data, struct task *task, uint64_t start,
 int schedule_task_init_edf(struct task *task, uint32_t uid,
 			   const struct task_ops *ops,
 			   void *data, uint16_t core, uint32_t flags)
+{
+	return schedule_task_init_edf_with_budget(task, uid, ops, data,
+						  core, flags, 0);
+}
+
+int schedule_task_init_edf_with_budget(struct task *task, uint32_t uid,
+				       const struct task_ops *ops,
+				       void *data, uint16_t core,
+				       uint32_t flags, uint32_t cycles_budget)
 {
 	struct edf_task_pdata *edf_pdata = NULL;
 	int ret = 0;
@@ -174,6 +214,8 @@ int schedule_task_init_edf(struct task *task, uint32_t uid,
 			      task->core, NULL, 0) < 0)
 		goto error;
 
+	edf_pdata->budget = cycles_budget;
+
 	/* flush for slave core */
 	if (cpu_is_slave(task->core))
 		dcache_writeback_invalidate_region(edf_pdata,
@@ -191,6 +233,7 @@ int schedule_task_init_edf(struct task *task, uint32_t uid,
 
 static int schedule_edf_task_running(void *data, struct task *task)
 {
+	struct edf_schedule_data *edf_sch = data;
 	struct edf_task_pdata *edf_pdata = edf_sch_get_pdata(task);
 	uint32_t flags;
 
@@ -201,6 +244,13 @@ static int schedule_edf_task_running(void *data, struct task *task)
 	task_context_set(edf_pdata->ctx);
 	task->state = SOF_TASK_STATE_RUNNING;
 
+	/* if budget is not set then it's not budgeted task */
+	if (edf_pdata->budget) {
+		timer_set(cpu_timer_get(), timer_get_system(cpu_timer_get())
+			  + edf_pdata->budget);
+		timer_enable(cpu_timer_get(), edf_sch, cpu_get_id());
+	}
+
 	irq_local_enable(flags);
 
 	return 0;
@@ -287,6 +337,8 @@ int scheduler_init_edf(void)
 	interrupt_register(edf_sch->irq, edf_scheduler_run, edf_sch);
 	interrupt_enable(edf_sch->irq, edf_sch);
 
+	timer_register(cpu_timer_get(), edf_scheduler_run, edf_sch);
+
 	return 0;
 }
 
@@ -297,6 +349,8 @@ static void scheduler_free_edf(void *data)
 
 	irq_local_disable(flags);
 
+	timer_unregister(cpu_timer_get(), edf_sch);
+
 	/* disable and unregister EDF scheduler interrupt */
 	interrupt_disable(edf_sch->irq, edf_sch);
 	interrupt_unregister(edf_sch->irq, edf_sch);