Add a program to test the performance of signals

.gitignore

@@ -2,3 +2,5 @@ shmem
 shmem_affinity
 kernel
 kernel_affinity
+signals
+signals_affinity

Makefile

@@ -1,5 +1,5 @@
-all: shmem shmem_affinity kernel kernel_affinity
-run: run_shmem run_kernel run_shmem_affinity run_kernel_affinity
+all: shmem shmem_affinity kernel kernel_affinity signals signals_affinity
+run: run_shmem run_kernel run_shmem_affinity run_kernel_affinity run_signals
 
 shmem:
 	$(CC) -std=c11 -DSHMEM $(CFLAGS) -lpthread -lrt -o shmem test.c
@@ -25,5 +25,15 @@ run_kernel: kernel
 run_kernel_affinity: kernel_affinity
 	@./kernel_affinity
 
+signals:
+	$(CC) -std=c11 $(CFLAGS) -lpthread -o signals signals.c
+
+signals_affinity:
+	$(CC) -std=c11 -DAFFINITY $(CFLAGS) -lpthread -o signals_affinity signals.c
+
+run_signals:
+	@./signals
+	@./signals_affinity
+
 clean:
-	rm -rf shmem shmem_affinity kernel kernel_affinity
+	rm -rf shmem shmem_affinity kernel kernel_affinity signals signals_affinity

signals.c

@@ -0,0 +1,113 @@
+#define _GNU_SOURCE
+#define _XOPEN_SOURCE (700)
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <sched.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <semaphore.h>
+#include <stdio.h>
+
+#include "time.c"
+
+#define CONSUMER(p) ((p) == 0)
+
+#ifdef AFFINITY
+#define STR "AFFINITY "
+#else // AFFINITY
+#define STR ""
+#endif // AFFINITY
+
+#define LIMIT ((size_t) 100000000)
+
+#define LIMIT2 (LIMIT / 2)
+
+unsigned int nsignals;
+pid_t parent;
+pid_t child;
+sem_t sem;
+
+void sighandler(int sig)
+{
+	nsignals += 1;
+	if (CONSUMER(child))
+	{
+		kill(parent, SIGUSR1);
+		if (nsignals >= LIMIT2) sem_post(&sem);
+	}
+	else if (nsignals < LIMIT2) kill(child, SIGUSR1);
+	else sem_post(&sem);
+}
+
+int main()
+{
+	cpu_set_t set;
+	TimeSpec start, end, diff;
+	struct sigaction sa;
+	int status;
+
+	parent = getpid();
+
+	nice(-20);
+
+	sigemptyset(&sa.sa_mask);
+	sa.sa_handler = sighandler;
+	sa.sa_flags = SA_RESTART;
+
+	sigaction(SIGUSR1, &sa, NULL);
+
+	child = fork();
+
+	if (child < 0) err("fork failed", 1);
+
+	sem_init(&sem, 0, 0);
+
+#ifdef AFFINITY
+	CPU_ZERO(&set);
+
+	if (CONSUMER(child)) CPU_SET(1, &set);
+	else CPU_SET(0, &set);
+
+	if (sched_setaffinity(0, sizeof(cpu_set_t), &set) < 0)
+	{
+		err("could not set cpu affinity", 2);
+	}
+#endif // AFFINITY
+
+	if (!CONSUMER(child))
+	{
+		ts_time(&start);
+		kill(child, SIGUSR1);
+	}
+
+	sem_wait(&sem);
+
+	if (!CONSUMER(child))
+	{
+		ts_time(&end);
+
+		waitpid(child, &status, 0);
+
+		if (WEXITSTATUS(status) != 0) err("child exited bad", 11);
+
+		diff = ts_diff(end, start);
+
+		printf(STR "SIGNALS: ");
+
+		ts_print(diff, LIMIT);
+
+		printf("\n");
+	}
+
+	sem_destroy(&sem);
+
+	return 0;
+}

test.c

@@ -82,12 +82,6 @@ typedef union size
 
 #endif // SHMEM
 
-static void err(char* msg, int exit_code)
-{
-	fprintf(stderr, "error: %s\n", msg);
-	exit(exit_code);
-}
-
 #ifdef SHMEM
 static Shmem* shmem_create(void)
 {

time.c

@@ -1,6 +1,12 @@
 #include <stdio.h>
 #include <time.h>
 
+static void err(char* msg, int exit_code)
+{
+	fprintf(stderr, "error: %s\n", msg);
+	exit(exit_code);
+}
+
 typedef struct timespec TimeSpec;
 
 unsigned long pow10(unsigned long p)