Fix nOS-V task pause and add regression test

emu_nosv.c

@@ -241,11 +241,14 @@ pre_task_end(struct ovni_emu *emu)
 }
 
 static void
-pre_task_not_running(struct ovni_emu *emu)
+pre_task_not_running(struct ovni_emu *emu, struct nosv_task *task)
 {
 	struct ovni_ethread *th;
 	th = emu->cur_thread;
 
+	if(task->state == TASK_ST_RUNNING)
+		die("task is still running\n");
+
 	chan_set(&th->chan[CHAN_NOSV_TASKID], 0);
 	chan_set(&th->chan[CHAN_NOSV_TYPE], 0);
 	chan_set(&th->chan[CHAN_NOSV_APPID], 0);
@@ -286,7 +289,7 @@ pre_task_running(struct ovni_emu *emu, struct nosv_task *task)
 
 static void
 pre_task_switch(struct ovni_emu *emu, struct nosv_task *prev_task,
-		struct nosv_task *next_task)
+		struct nosv_task *next_task, int newtask)
 {
 	struct ovni_ethread *th;
 
@@ -298,6 +301,15 @@ pre_task_switch(struct ovni_emu *emu, struct nosv_task *prev_task,
 	if(prev_task == next_task)
 		die("cannot switch to the same task\n");
 
+	if(newtask && prev_task->state != TASK_ST_RUNNING)
+		die("previous task must not be no longer running\n");
+
+	if(!newtask && prev_task->state != TASK_ST_DEAD)
+		die("previous task must be dead\n");
+
+	if(next_task->state != TASK_ST_RUNNING)
+		die("next task must be running\n");
+
 	if(next_task->id == 0)
 		die("next task id cannot be 0\n");
 
@@ -319,13 +331,26 @@ pre_task_switch(struct ovni_emu *emu, struct nosv_task *prev_task,
 		chan_set(&th->chan[CHAN_NOSV_TYPE], next_task->type->gid);
 }
 
+static int
+is_running_task(struct ovni_emu *emu, struct nosv_task **ptask)
+{
+	struct nosv_task *task = emu->cur_thread->task_stack;
+	if(task && task->state == TASK_ST_RUNNING)
+	{
+		*ptask = task;
+		return 1;
+	}
+
+	return 0;
+}
+
 static void
 pre_task(struct ovni_emu *emu)
 {
-	struct nosv_task *prev_task, *next_task;
+	struct nosv_task *prev_task = NULL;
-
+	int was_running_task = is_running_task(emu, &prev_task);
-	prev_task = emu->cur_thread->task_stack;
 
+	/* Update the emulator state, but don't modify the channels yet */
 	switch(emu->cur_ev->header.value)
 	{
 		case 'c': pre_task_create(emu); break;
@@ -337,17 +362,33 @@ pre_task(struct ovni_emu *emu)
 			  abort();
 	}
 
-	next_task = emu->cur_thread->task_stack;
+	struct nosv_task *next_task = NULL;
+	int runs_task_now = is_running_task(emu, &next_task);
 
-	/* Unless we're creating a task, register the switch */
+	/* Now that we know if the emulator was running a task before
-	if(emu->cur_ev->header.value != 'c')
+	 * or if it's running one now, update the channels accordingly. */
+	switch(emu->cur_ev->header.value)
 	{
-		if(next_task == NULL)
+		case 'x': /* Execute: either a nested task or a new one */
-			pre_task_not_running(emu);
+			if(was_running_task)
-		else if(prev_task == NULL)
+				pre_task_switch(emu, prev_task, next_task, 1);
+			else
+				pre_task_running(emu, next_task);
+			break;
+		case 'e': /* End: either a nested task or the last one */
+			if(runs_task_now)
+				pre_task_switch(emu, prev_task, next_task, 0);
+			else
+				pre_task_not_running(emu, prev_task);
+			break;
+		case 'p': /* Pause */
+			pre_task_not_running(emu, prev_task);
+			break;
+		case 'r': /* Resume */
 			pre_task_running(emu, next_task);
-		else
+			break;
-			pre_task_switch(emu, prev_task, next_task);
+		default:
+			break;
 	}
 }
 

test/CMakeLists.txt

@@ -40,3 +40,4 @@ ovni_test("mp-rank" "mp-driver.sh")
 ovni_test("nosv-nested-tasks" "driver.sh")
 ovni_test("nosv-nested-tasks-bad" "driver.sh")
 ovni_test("nosv-task-types" "mp-driver.sh")
+ovni_test("nosv-pause" "mp-driver.sh")

test/nosv-pause.c

@@ -0,0 +1,211 @@
+/*
+ * Copyright (c) 2021-2022 Barcelona Supercomputing Center (BSC)
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#define _GNU_SOURCE
+
+#include "ovni.h"
+#include "compat.h"
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+static void
+fail(const char *msg)
+{
+	fprintf(stderr, "%s\n", msg);
+	abort();
+}
+
+static inline void
+emit_ev(char *mcv)
+{
+	struct ovni_ev ev = { 0 };
+
+	ovni_ev_set_mcv(&ev, mcv);
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_ev_emit(&ev);
+}
+
+#define INSTR_3ARG(name, mcv, ta, a, tb, b, tc, c)               \
+	static inline void name(ta a, tb b, tc c)                \
+	{                                                        \
+		struct ovni_ev ev = {0};                         \
+		ovni_ev_set_mcv(&ev, mcv);                       \
+		ovni_ev_set_clock(&ev, ovni_clock_now());        \
+		ovni_payload_add(&ev, (uint8_t *)&a, sizeof(a)); \
+		ovni_payload_add(&ev, (uint8_t *)&b, sizeof(b)); \
+		ovni_payload_add(&ev, (uint8_t *)&c, sizeof(c)); \
+		ovni_ev_emit(&ev);                                    \
+	}
+
+INSTR_3ARG(instr_thread_execute, "OHx", int32_t, cpu, int32_t, creator_tid, uint64_t, tag)
+
+static inline void
+instr_thread_end(void)
+{
+	struct ovni_ev ev = {0};
+
+	ovni_ev_set_mcv(&ev, "OHe");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_ev_emit(&ev);
+
+	/* Flush the events to disk before killing the thread */
+	ovni_flush();
+}
+
+static inline void
+instr_start(int rank, int nranks)
+{
+	char hostname[HOST_NAME_MAX];
+
+	if(gethostname(hostname, HOST_NAME_MAX) != 0)
+		fail("gethostname failed");
+
+	ovni_proc_init(1, hostname, getpid());
+
+	ovni_proc_set_rank(rank, nranks);
+
+	ovni_thread_init(gettid());
+
+	/* Only the rank 0 inform about all CPUs */
+	if(rank == 0)
+	{
+		/* Fake nranks cpus */
+		for(int i=0; i < nranks; i++)
+			ovni_add_cpu(i, i);
+	}
+
+	int curcpu = rank;
+
+	fprintf(stderr, "thread %d has cpu %d (ncpus=%d)\n",
+			gettid(), curcpu, nranks);
+
+	instr_thread_execute(curcpu, -1, 0);
+}
+
+static inline void
+instr_end(void)
+{
+	instr_thread_end();
+	ovni_thread_free();
+	ovni_proc_fini();
+}
+
+static void
+type_create(int32_t typeid)
+{
+	struct ovni_ev ev = {0};
+
+	ovni_ev_set_mcv(&ev, "VYc");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+
+	char buf[256];
+	char *p = buf;
+
+	size_t nbytes = 0;
+	memcpy(buf, &typeid, sizeof(typeid));
+	p += sizeof(typeid);
+	nbytes += sizeof(typeid);
+	sprintf(p, "testtype%d", typeid);
+	nbytes += strlen(p) + 1;
+
+	ovni_ev_jumbo_emit(&ev, (uint8_t *) buf, nbytes);
+}
+
+static void
+task_begin(int32_t id, uint32_t typeid)
+{
+	struct ovni_ev ev = {0};
+
+	ovni_ev_set_mcv(&ev, "VTc");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_payload_add(&ev, (uint8_t *) &id, sizeof(id));
+	ovni_payload_add(&ev, (uint8_t *) &typeid, sizeof(id));
+	ovni_ev_emit(&ev);
+
+	memset(&ev, 0, sizeof(ev));
+
+	ovni_ev_set_mcv(&ev, "VTx");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_payload_add(&ev, (uint8_t *) &id, sizeof(id));
+	ovni_ev_emit(&ev);
+}
+
+static void
+task_pause(int32_t id)
+{
+	struct ovni_ev ev = {0};
+
+	ovni_ev_set_mcv(&ev, "VTp");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_payload_add(&ev, (uint8_t *) &id, sizeof(id));
+	ovni_ev_emit(&ev);
+}
+
+static void
+task_resume(int32_t id)
+{
+	struct ovni_ev ev = {0};
+
+	ovni_ev_set_mcv(&ev, "VTr");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_payload_add(&ev, (uint8_t *) &id, sizeof(id));
+	ovni_ev_emit(&ev);
+}
+
+static void
+task_end(int32_t id)
+{
+	struct ovni_ev ev = {0};
+
+	ovni_ev_set_mcv(&ev, "VTe");
+	ovni_ev_set_clock(&ev, ovni_clock_now());
+	ovni_payload_add(&ev, (uint8_t *) &id, sizeof(id));
+	ovni_ev_emit(&ev);
+}
+
+int
+main(void)
+{
+	int rank = atoi(getenv("OVNI_RANK"));
+	int nranks = atoi(getenv("OVNI_NRANKS"));
+	instr_start(rank, nranks);
+
+	int us = 500;
+	uint32_t typeid = 1;
+
+	type_create(typeid);
+
+	task_begin(1, typeid);
+	usleep(us);
+	task_pause(1);
+	usleep(us);
+	task_resume(1);
+	usleep(us);
+	task_end(1);
+
+	instr_end();
+
+	return 0;
+}
+