[PATCH] Easy process shared semaphores

[fio.git] / fio.h

diff --git a/fio.h b/fio.h
index 0b25bb8d6d8ecca054be61d867b0f688bfd747cd..09e56d66cb4079cb013a1c9e8d55e9cafbe62d6f 100644 (file)
--- 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 @@ struct thread_data {
        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 void rate_throttle(struct thread_data *, unsigned long, unsigned int);
 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