From: Carl Worth <cworth@cworth.org>
Date: Tue, 12 Nov 2013 18:30:18 +0000 (-0800)
Subject: Use consistent argument order for subtract functions and macros.
X-Git-Url: https://git.cworth.org/git?p=fips;a=commitdiff_plain;h=39b71bb28a1ea89b694fe12f1d2d0e914ae528d7

Use consistent argument order for subtract functions and macros.

We were calling subtract_timestamp() on the line just before
TIMESPEC_DIFF() but with reversed argument order in the two. This
could obviously lead to convention. So we stick adopt the (a - b)
convention for both, (as well as the name "subtract" for both).
---

diff --git a/metrics.c b/metrics.c
index c52bf2e..7b2a558 100644
--- a/metrics.c
+++ b/metrics.c
@@ -819,9 +819,9 @@ metrics_collect_available (metrics_t *metrics)
 	}
 }
 
-/* Return the difference from ts0 to ts1 as floating-point seconds. */
-#define TIMESPEC_DIFF(ts0, ts1) (double) (ts1.tv_sec - ts0.tv_sec + \
-					  (ts1.tv_nsec - ts0.tv_nsec) / 1e9)
+/* Subtract timespec values: Return (a - b) in seconds as a double. */
+#define SUBTRACT_TIMESPEC(a, b) (double) (a.tv_sec - b.tv_sec + \
+					  (a.tv_nsec - b.tv_nsec) / 1e9)
 
 void
 metrics_end_frame_pre_swap (metrics_t *metrics)
@@ -864,7 +864,8 @@ metrics_end_frame_pre_swap (metrics_t *metrics)
 		latency_ns = subtract_timestamp (swap_end_timestamp,
 						 metrics->swap_begin_timestamp);
 
-		cpu_time = TIMESPEC_DIFF (metrics->previous_cpu_time_ts, metrics->cpu_time_ts);
+		cpu_time = SUBTRACT_TIMESPEC (metrics->cpu_time_ts,
+					      metrics->previous_cpu_time_ts);
 
 		/* We've waited one frame to ensure we have a timestamp
 		 * result. So the time we've actually measured here is