rt-tests: cyclictest: Add option to specify main pid affinity

Move error handling for setting the affinity of the main thread into a separate function.
This prevents duplicating the code in the next commit, where the main thread pid can be restricted to one of two bitmasks depending on the passed parameters.

Signed-off-by Jonathan Schwender <[email protected]>

---
 src/cyclictest/cyclictest.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

src/cyclictest/cyclictest.c +0 -0

index 59dda19..3bab3b2 100644

src/cyclictest/cyclictest.c +12 -7

+static void set_main_thread_affinity(struct bitmask *cpumask)
+{
+	int res;
+
+	errno = 0;
+	res = numa_sched_setaffinity(getpid(), cpumask);
+	if (res != 0)
+		warn("Couldn't setaffinity in main thread: %s\n",
+		     strerror(errno));
+}
+
 int main(int argc, char **argv)
 {
 	sigset_t sigset;

@@ -1792,13 +1803,7 @@ int main(int argc, char **argv)
 
 	/* Restrict the main pid to the affinity specified by the user */
 	if (affinity_mask != NULL) {
-		int res;
-
-		errno = 0;
-		res = numa_sched_setaffinity(getpid(), affinity_mask);
-		if (res != 0)
-			warn("Couldn't setaffinity in main thread: %s\n", strerror(errno));
-
+		set_main_thread_affinity(affinity_mask);
 		if (verbose)
 			printf("Using %u cpus.\n",
 				numa_bitmask_weight(affinity_mask));

Signature · 1 line

2.31.1

How about set_thread_affinity() since you want to use the function for the main thread plus other threads.

src/cyclictest/cyclictest.c static void write_stats(FILE *f, void *data) · line 1781

Quoted 12 lines

src/cyclictest/cyclictest.c +11 -0

+static void set_main_thread_affinity(struct bitmask *cpumask)
+{
+	int res;
+
+	errno = 0;
+	res = numa_sched_setaffinity(getpid(), cpumask);
+	if (res != 0)
+		warn("Couldn't setaffinity in main thread: %s\n",
+		     strerror(errno));
+}
+

This allows the user to specify a separate cpuset for the main pid, e.g. on a housekeeping CPU.
If --mainaffinity is not specified, but --affinity is, then the current behaviour is preserved and the main thread is bound to the cpuset specified by --affinity

Signed-off-by Jonathan Schwender <[email protected]>

---
 src/cyclictest/cyclictest.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

src/cyclictest/cyclictest.c +0 -0

index 3bab3b2..a2103c7 100644

src/cyclictest/cyclictest.c static void display_help(int error) · line 840

Quoted 3 lines

src/cyclictest/cyclictest.c +2 -0

+	       "         --mainaffinity=[CPUSET]  Run the main thread on CPU #N. This only affects\n"
+	       "                           the main thread and not the measurement threads\n"

The main thread is allowed to run on any CPU which CPUSET specifies. CPU #N does not really make sense.

While at it, please update man page accordingly.

Thanks,
Daniel

This allows the user to specify a separate cpuset for the main pid, e.g. on a housekeeping CPU.
If --mainaffinity is not specified, but --affinity is, then the current behaviour is preserved and the main thread is bound to the cpuset specified by --affinity

Signed-off-by Jonathan Schwender <[email protected]>

---
 src/cyclictest/cyclictest.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

src/cyclictest/cyclictest.c +15 -1

index 3bab3b2..a2103c7 100644
@@ -836,6 +836,8 @@ static void display_help(int error)
 	       "	 --laptop	   Save battery when running cyclictest\n"
 	       "			   This will give you poorer realtime results\n"
 	       "			   but will not drain your battery so quickly\n"
+	       "         --mainaffinity=[CPUSET]  Run the main thread on CPU #N. This only affects\n"
+	       "                           the main thread and not the measurement threads\n"
 	       "-m       --mlockall        lock current and future memory allocations\n"
 	       "-M       --refresh_on_max  delay updating the screen until a new max\n"
 	       "			   latency is hit. Useful for low bandwidth.\n"

@@ -891,6 +893,7 @@ static int quiet;
 static int interval = DEFAULT_INTERVAL;
 static int distance = -1;
 static struct bitmask *affinity_mask = NULL;
+static struct bitmask *main_affinity_mask = NULL;
 static int smp = 0;
 static int setaffinity = AFFINITY_UNSPECIFIED;
 

@@ -944,7 +947,7 @@ enum option_values {
 	OPT_AFFINITY=1, OPT_BREAKTRACE, OPT_CLOCK,
 	OPT_DISTANCE, OPT_DURATION, OPT_LATENCY,
 	OPT_FIFO, OPT_HISTOGRAM, OPT_HISTOFALL, OPT_HISTFILE,
-	OPT_INTERVAL, OPT_LOOPS, OPT_MLOCKALL, OPT_REFRESH,
+	OPT_INTERVAL, OPT_LOOPS, OPT_MAINAFFINITY, OPT_MLOCKALL, OPT_REFRESH,
 	OPT_NANOSLEEP, OPT_NSECS, OPT_OSCOPE, OPT_PRIORITY,
 	OPT_QUIET, OPT_PRIOSPREAD, OPT_RELATIVE, OPT_RESOLUTION,
 	OPT_SYSTEM, OPT_SMP, OPT_THREADS, OPT_TRIGGER,

@@ -981,6 +984,7 @@ static void process_options(int argc, char *argv[], int max_cpus)
 			{"interval",         required_argument, NULL, OPT_INTERVAL },
 			{"laptop",	     no_argument,	NULL, OPT_LAPTOP },
 			{"loops",            required_argument, NULL, OPT_LOOPS },
+			{"mainaffinity",     required_argument, NULL, OPT_MAINAFFINITY},
 			{"mlockall",         no_argument,       NULL, OPT_MLOCKALL },
 			{"refresh_on_max",   no_argument,       NULL, OPT_REFRESH },
 			{"nsecs",            no_argument,       NULL, OPT_NSECS },

@@ -1083,6 +1087,16 @@ static void process_options(int argc, char *argv[], int max_cpus)
 		case 'l':
 		case OPT_LOOPS:
 			max_cycles = atoi(optarg); break;
+		case OPT_MAINAFFINITY:
+			if (optarg) {
+				parse_cpumask(optarg, max_cpus, &main_affinity_mask);
+			} else if (optind < argc &&
+			           (atoi(argv[optind]) ||
+			            argv[optind][0] == '0' ||
+			            argv[optind][0] == '!')) {
+				parse_cpumask(argv[optind], max_cpus, &main_affinity_mask);
+			}
+			break;
 		case 'm':
 		case OPT_MLOCKALL:
 			lockall = 1; break;

src/cyclictest/cyclictest.c +1 -0

+	} else if (affinity_mask != NULL) {
 		set_main_thread_affinity(affinity_mask);
 		if (verbose)
 			printf("Using %u cpus.\n",

Signature · 1 line

2.31.1

This allows the user to specify a separate cpuset for the main pid, e.g. on a housekeeping CPU.
If --mainaffinity is not specified, but --affinity is, then the current behaviour is preserved and the main thread is bound to the cpuset specified by --affinity

Signed-off-by Jonathan Schwender <[email protected]>

---
 src/cyclictest/cyclictest.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

src/cyclictest/cyclictest.c +15 -1

index 3bab3b2..a2103c7 100644
@@ -836,6 +836,8 @@ static void display_help(int error)
 	       "	 --laptop	   Save battery when running cyclictest\n"
 	       "			   This will give you poorer realtime results\n"
 	       "			   but will not drain your battery so quickly\n"
+	       "         --mainaffinity=[CPUSET]  Run the main thread on CPU #N. This only affects\n"
+	       "                           the main thread and not the measurement threads\n"
 	       "-m       --mlockall        lock current and future memory allocations\n"
 	       "-M       --refresh_on_max  delay updating the screen until a new max\n"
 	       "			   latency is hit. Useful for low bandwidth.\n"

@@ -891,6 +893,7 @@ static int quiet;
 static int interval = DEFAULT_INTERVAL;
 static int distance = -1;
 static struct bitmask *affinity_mask = NULL;
+static struct bitmask *main_affinity_mask = NULL;
 static int smp = 0;
 static int setaffinity = AFFINITY_UNSPECIFIED;
 

@@ -944,7 +947,7 @@ enum option_values {
 	OPT_AFFINITY=1, OPT_BREAKTRACE, OPT_CLOCK,
 	OPT_DISTANCE, OPT_DURATION, OPT_LATENCY,
 	OPT_FIFO, OPT_HISTOGRAM, OPT_HISTOFALL, OPT_HISTFILE,
-	OPT_INTERVAL, OPT_LOOPS, OPT_MLOCKALL, OPT_REFRESH,
+	OPT_INTERVAL, OPT_LOOPS, OPT_MAINAFFINITY, OPT_MLOCKALL, OPT_REFRESH,
 	OPT_NANOSLEEP, OPT_NSECS, OPT_OSCOPE, OPT_PRIORITY,
 	OPT_QUIET, OPT_PRIOSPREAD, OPT_RELATIVE, OPT_RESOLUTION,
 	OPT_SYSTEM, OPT_SMP, OPT_THREADS, OPT_TRIGGER,

@@ -981,6 +984,7 @@ static void process_options(int argc, char *argv[], int max_cpus)
 			{"interval",         required_argument, NULL, OPT_INTERVAL },
 			{"laptop",	     no_argument,	NULL, OPT_LAPTOP },
 			{"loops",            required_argument, NULL, OPT_LOOPS },
+			{"mainaffinity",     required_argument, NULL, OPT_MAINAFFINITY},
 			{"mlockall",         no_argument,       NULL, OPT_MLOCKALL },
 			{"refresh_on_max",   no_argument,       NULL, OPT_REFRESH },
 			{"nsecs",            no_argument,       NULL, OPT_NSECS },

@@ -1083,6 +1087,16 @@ static void process_options(int argc, char *argv[], int max_cpus)
 		case 'l':
 		case OPT_LOOPS:
 			max_cycles = atoi(optarg); break;
+		case OPT_MAINAFFINITY:
+			if (optarg) {
+				parse_cpumask(optarg, max_cpus, &main_affinity_mask);
+			} else if (optind < argc &&
+			           (atoi(argv[optind]) ||
+			            argv[optind][0] == '0' ||
+			            argv[optind][0] == '!')) {
+				parse_cpumask(argv[optind], max_cpus, &main_affinity_mask);
+			}
+			break;
 		case 'm':
 		case OPT_MLOCKALL:
 			lockall = 1; break;

src/cyclictest/cyclictest.c +1 -0

+	} else if (affinity_mask != NULL) {
 		set_main_thread_affinity(affinity_mask);
 		if (verbose)
 			printf("Using %u cpus.\n",

Signature · 1 line

2.31.1

Quoted 10 lines

This allows the user to specify a separate cpuset for the main pid, e.g. on a housekeeping CPU.
If --mainaffinity is not specified, but --affinity is, then the current behaviour is preserved and the main thread is bound to the cpuset specified by --affinity

(quoted diff) +0 -0

@@ -1802,7 +1816,9 @@ int main(int argc, char **argv)
  	}
 

src/cyclictest/cyclictest.c int main(int argc, char **argv) · line 1820

Quoted 4 lines

src/cyclictest/cyclictest.c +2 -1

  	/* Restrict the main pid to the affinity specified by the user */
-	if (affinity_mask != NULL) {
+	if (main_affinity_mask != NULL) {
+		set_main_thread_affinity(main_affinity_mask);

Am I missing something here, if there is a main_affinity_mask we set that but then skip over the affinity_mask. Don't we want to check both?

Quoted 9 lines

src/cyclictest/cyclictest.c +1 -0

+	} else if (affinity_mask != NULL) {
  		set_main_thread_affinity(affinity_mask);
  		if (verbose)
  			printf("Using %u cpus.\n",

Signature · 1 line

2.31.1