[PATCH] Easy process shared semaphores
We really need a pshared semaphore, but those aren't always available.
Just implement a cruddy local semaphore type, fio only really needs
to signal start/stop conditions.
diff --git a/fio.h b/fio.h
index 0b25bb8..09e56d6 100644
--- a/fio.h
+++ b/fio.h
@@ -6,7 +6,6 @@
#include <pthread.h>
#include <sys/time.h>
#include <sys/resource.h>
-#include <semaphore.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
@@ -205,7 +204,7 @@
unsigned long long zone_bytes;
unsigned long long this_io_bytes[2];
unsigned long long last_pos;
- sem_t mutex;
+ volatile int mutex;
os_random_state_t random_state;
unsigned long *file_map;
@@ -391,4 +390,28 @@
extern int parse_options(int, char **);
extern int init_random_state(struct thread_data *);
+/*
+ * This is a pretty crappy semaphore implementation, but with the use that fio
+ * has (just signalling start/go conditions), it doesn't have to be better.
+ * Naturally this would not work for any type of contended semaphore or
+ * for real locking.
+ */
+static inline void fio_sem_init(volatile int volatile *sem, int val)
+{
+ *sem = val;
+}
+
+static inline void fio_sem_down(volatile int volatile *sem)
+{
+ while (*sem == 0)
+ usleep(10000);
+
+ (*sem)--;
+}
+
+static inline void fio_sem_up(volatile int volatile *sem)
+{
+ (*sem)++;
+}
+
#endif