tools: rename 'rtex' tool to 'pgflt'

The rtex tool only demonstrates prefaultingn to avoid runtime
page faults. It makes more sense to call it pgflt.

Signed-off-by: John Ogness <john.ogness@linutronix.de>

1 files changed, 72 insertions, 0 deletions

diff --git a/schulung_tools/pgflt/rt.c b/schulung_tools/pgflt/rt.c
new file mode 100644
index 0000000..86a6506
--- /dev/null
+++ b/schulung_tools/pgflt/rt.c
@@ -0,0 +1,72 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <malloc.h>
+#include <sys/mman.h>
+
+extern void timestamp(const char *msg, int val);
+extern void testfunc_malloc(void);
+extern void testfunc_deepstack(void);
+
+void prefault_stack(void)
+{
+#define STACK_SIZE (7680 * 1024) /* 7.5 MiB */
+	char buf[STACK_SIZE];
+	long pagesize;
+	int i;
+
+	pagesize = sysconf(_SC_PAGESIZE);
+
+	for (i = 0; i < STACK_SIZE; i += pagesize)
+		buf[i] = 0;
+}
+
+void prefault_heap(void)
+{
+#define HEAP_SIZE (20 * 1024 * 1024) /* 20 MiB */
+	long pagesize;
+	char *buf;
+	int i;
+
+	pagesize = sysconf(_SC_PAGESIZE);
+
+	buf = malloc(HEAP_SIZE);
+	if (!buf) {
+		fprintf(stderr, "MALLOC FAILED: %s:%d\n", __FILE__, __LINE__);
+		return;
+	}
+
+	for (i = 0; i < HEAP_SIZE; i += pagesize)
+		buf[i] = 0;
+
+	free(buf);
+}
+
+void setup_rt(unsigned int opts)
+{
+	if (opts & 0x1) {
+		if (mallopt(M_TRIM_THRESHOLD, -1) == 0) {
+			fprintf(stderr, "MALLOPT FAILED: %s:%d\n",
+				__FILE__, __LINE__);
+		}
+
+		if (mallopt(M_MMAP_MAX, 0) == 0) {
+			fprintf(stderr, "MALLOPT FAILED: %s:%d\n",
+				__FILE__, __LINE__);
+		}
+	}
+
+	if (opts & 0x2) {
+		if (mlockall(MCL_CURRENT | MCL_FUTURE) == -1) {
+			fprintf(stderr, "MLOCKALL FAILED: %s:%d\n",
+				__FILE__, __LINE__);
+		}
+	}
+
+	if (opts & 0x4)
+		prefault_stack();
+
+	if (opts & 0x8)
+		prefault_heap();
+}
+