libglusterfs: add functions to calculate time difference

Add gf_tvdiff() and gf_tsdiff() to calculate the difference
between 'struct timeval' and 'struct timespec' values, use
them where appropriate.

Change-Id: I172be06ee84e99a1da76847c15e5ea3fbc059338
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Updates: #1002

2 files changed, 33 insertions, 2 deletions

diff --git a/libglusterfs/src/glusterfs/common-utils.h b/libglusterfs/src/glusterfs/common-utils.h
index d605beae461..c998d515fae 100644
--- a/libglusterfs/src/glusterfs/common-utils.h
+++ b/libglusterfs/src/glusterfs/common-utils.h
@@ -1219,4 +1219,36 @@ gf_time(void)
     return time(NULL);
 }
 
+/* Return delta value in microseconds. */
+
+static inline double
+gf_tvdiff(struct timeval *start, struct timeval *end)
+{
+    struct timeval t;
+
+    if (start->tv_usec > end->tv_usec)
+        t.tv_sec = end->tv_sec - 1, t.tv_usec = end->tv_usec + 1000000;
+    else
+        t.tv_sec = end->tv_sec, t.tv_usec = end->tv_usec;
+
+    return (double)(t.tv_sec - start->tv_sec) * 1e6 +
+           (double)(t.tv_usec - start->tv_usec);
+}
+
+/* Return delta value in nanoseconds. */
+
+static inline double
+gf_tsdiff(struct timespec *start, struct timespec *end)
+{
+    struct timespec t;
+
+    if (start->tv_nsec > end->tv_nsec)
+        t.tv_sec = end->tv_sec - 1, t.tv_nsec = end->tv_nsec + 1000000000;
+    else
+        t.tv_sec = end->tv_sec, t.tv_nsec = end->tv_nsec;
+
+    return (double)(t.tv_sec - start->tv_sec) * 1e9 +
+           (double)(t.tv_nsec - start->tv_nsec);
+}
+
 #endif /* _COMMON_UTILS_H */
diff --git a/libglusterfs/src/latency.c b/libglusterfs/src/latency.c
index 15b397c3799..8ec89093d41 100644
--- a/libglusterfs/src/latency.c
+++ b/libglusterfs/src/latency.c
@@ -30,8 +30,7 @@ gf_update_latency(call_frame_t *frame)
     if (!(begin->tv_sec && end->tv_sec))
         goto out;
 
-    elapsed = (end->tv_sec - begin->tv_sec) * 1e9 +
-              (end->tv_nsec - begin->tv_nsec);
+    elapsed = gf_tsdiff(begin, end);
 
     if (frame->op < 0 || frame->op >= GF_FOP_MAXVALUE) {
         gf_log("[core]", GF_LOG_WARNING, "Invalid frame op value: %d",