add page fault prober

Makefile

@@ -22,5 +22,9 @@ build/guess_cpu_speed: src/guess_cpu_speed.c src/timer.c
 	mkdir -p build
 	gcc -o build/guess_cpu_speed src/guess_cpu_speed.c $(CFLAGS)
 
+build/page_fault_prober: src/page_fault_prober.c
+	mkdir -p build
+	gcc -o build/page_fault_prober src/page_fault_prober.c $(CFLAGS)
+
 clean:
 	rm -r build

src/page_fault_prober.c

@@ -0,0 +1,49 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#define RPROF_IMPLEMENTATION
+#include "rprof.h"
+
+int main(int argc, char **argv) {
+	if (argc != 3) {
+		printf("Usage: %s <output-file> <page-count>\n", argv[0]);
+		return -1;
+	}
+
+	uint64_t page_size = sysconf(_SC_PAGESIZE);
+	char *output_path = argv[1];
+	uint64_t page_count = atol(argv[2]);
+
+	char *memory = mmap(NULL, page_size * page_count, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
+	if (memory == NULL) {
+		perror("mmap");
+		return -1;
+	}
+
+	// char *memory = malloc(page_size * page_count);
+	// if (memory == NULL) {
+	// 	perror("malloc");
+	// 	return -1;
+	// }
+
+	FILE *f = fopen(output_path, "w");
+	if (f == NULL) {
+		perror("fopen");
+		return -1;
+	}
+
+	for (int i = 0; i < page_count; i++) {
+		uint64_t fault_count = read_page_faults();
+		memory[i*page_size] = i;
+		uint64_t page_fault_diff = read_page_faults() - fault_count;
+
+		char line[128];
+		int line_length = snprintf(line, sizeof(line), "%d,%lu\n", i+1, page_fault_diff);
+		fwrite(line, line_length, 1, f);
+	}
+
+	return 0;
+}

src/repetition_tester.c

@@ -71,15 +71,6 @@ void print_repetition_time(char *label, float cpu_time, uint64_t bytes, uint64_t
 	}
 }
 
-uint64_t read_page_faults() {
-	// NOTE: ru_minflt  the number of page faults serviced without any I/O activity.
-	//       ru_majflt  the number of page faults serviced that required I/O activity.
-	struct rusage usage = {};
-    getrusage(RUSAGE_SELF, &usage);
-    int Result = usage.ru_minflt + usage.ru_majflt;
-    return Result;
-}
-
 bool repetition_tester_continue(struct repetition_tester *tester, struct repetition_results *results) {
 	if (tester->state != STATE_RUNNING) {
 		return false;

src/rprof.h

@@ -142,6 +142,19 @@ static uint64_t rprof_get_cpu_timer_hz(uint64_t measure_time_ms)
 	}
 }
 
+// ------------------------ Page faults -------------------------
+
+#include <sys/resource.h>
+
+uint64_t read_page_faults() {
+	// NOTE: ru_minflt  the number of page faults serviced without any I/O activity.
+	//       ru_majflt  the number of page faults serviced that required I/O activity.
+	struct rusage usage = {};
+    getrusage(RUSAGE_SELF, &usage);
+    int Result = usage.ru_minflt + usage.ru_majflt;
+    return Result;
+}
+
 // ------------------------ Profiling -------------------------
 
 void rprof_init()

src/tests.c

@@ -166,7 +166,5 @@ int main()
 		}
 	}
 
-	printf("page faults: %lu\n", read_page_faults());
-
 	return 0;
 }