[PATCH] Make the libaio fsync fallback really work
[fio.git] / time.c
diff --git a/time.c b/time.c
index d0ecbe5c831af59f857164af9fa433d96eaceda0..08ef078277ba125d43d1ce956db2ea92091e0793 100644 (file)
--- a/time.c
+++ b/time.c
@@ -4,6 +4,7 @@
 #include "fio.h"
 
 static struct timeval genesis;
+static unsigned long ns_granularity;
 
 unsigned long utime_since(struct timeval *s, struct timeval *e)
 {
@@ -74,28 +75,36 @@ void __usec_sleep(unsigned int usec)
 
 void usec_sleep(struct thread_data *td, unsigned long usec)
 {
-       struct timespec req, rem;
-
-       req.tv_sec = usec / 1000000;
-       req.tv_nsec = usec * 1000 - req.tv_sec * 1000000;
+       struct timespec req;
+       struct timeval tv;
 
        do {
-               if (usec < 5000) {
+               unsigned long ts = usec;
+
+               if (usec < ns_granularity) {
                        __usec_sleep(usec);
                        break;
                }
 
-               rem.tv_sec = rem.tv_nsec = 0;
-               if (nanosleep(&req, &rem) < 0)
-                       break;
+               ts = usec - ns_granularity;
 
-               if ((rem.tv_sec + rem.tv_nsec) == 0)
+               if (ts >= 1000000) {
+                       req.tv_sec = ts / 1000000;
+                       ts -= 1000000 * req.tv_sec;
+               } else
+                       req.tv_sec = 0;
+
+               req.tv_nsec = ts * 1000;
+               fio_gettime(&tv, NULL);
+
+               if (nanosleep(&req, NULL) < 0)
                        break;
 
-               req.tv_nsec = rem.tv_nsec;
-               req.tv_sec = rem.tv_sec;
+               ts = utime_since_now(&tv);
+               if (ts >= usec)
+                       break;
 
-               usec = rem.tv_sec * 1000000 + rem.tv_nsec / 1000;
+               usec -= ts;
        } while (!td->terminate);
 }
 
@@ -131,7 +140,28 @@ unsigned long mtime_since_genesis(void)
 
 static void fio_init time_init(void)
 {
+       int i;
+
        fio_gettime(&genesis, NULL);
+
+       /*
+        * Check the granularity of the nanosleep function
+        */
+       for (i = 0; i < 10; i++) {
+               struct timeval tv;
+               struct timespec ts;
+               unsigned long elapsed;
+
+               fio_gettime(&tv, NULL);
+               ts.tv_sec = 0;
+               ts.tv_nsec = 1000;
+
+               nanosleep(&ts, NULL);
+               elapsed = utime_since_now(&tv);
+
+               if (elapsed > ns_granularity)
+                       ns_granularity = elapsed;
+       }
 }
 
 void fill_start_time(struct timeval *t)