[GitHub] [nuttx] jlaitine commented on a diff in pull request #8371: Change sec2tick macros to round up

["jlaitine (via GitHub)" <gi...@apache.org>]

jlaitine commented on code in PR #8371:
URL: https://github.com/apache/nuttx/pull/8371#discussion_r1091664006


##########
include/nuttx/clock.h:
##########
@@ -145,41 +145,49 @@
  * preferred for that reason (at the risk of overflow)
  */
 
-#define TICK_PER_HOUR         (USEC_PER_HOUR / USEC_PER_TICK)            /* Truncates! */
-#define TICK_PER_MIN          (USEC_PER_MIN  / USEC_PER_TICK)            /* Truncates! */
-#define TICK_PER_SEC          (USEC_PER_SEC  / USEC_PER_TICK)            /* Truncates! */
-#define TICK_PER_MSEC         (USEC_PER_MSEC / USEC_PER_TICK)            /* Truncates! */
-#define TICK_PER_DSEC         (USEC_PER_DSEC / USEC_PER_TICK)            /* Truncates! */
-#define TICK_PER_HSEC         (USEC_PER_HSEC / USEC_PER_TICK)            /* Truncates! */
+/* TICK_PER_* truncates! */
 
-#define MSEC_PER_TICK         (USEC_PER_TICK / USEC_PER_MSEC)            /* Truncates! */
-#define NSEC_PER_TICK         (USEC_PER_TICK * NSEC_PER_USEC)            /* Exact */
+#define TICK_PER_HOUR         (USEC_PER_HOUR / USEC_PER_TICK)

Review Comment:
   Intuitively I'd say no:
   
   - The intended use for those macros is different than of those that I was now changing
   - There is a comment warning about these macros a bit above, describing the truncation/inaccuracy
   - They haven't been used in many places (basically only TICK_PER_SEC is used) and in most (normal) cases it wouldn't make any difference either
   - The TICK_PER_SEC is used in clock_ticks2time.c in a similar way as some other OSs do tick->timespec conversion, so it is currenly expecting it to truncate.
   - They are also not directly related to the SEC2TICK macros, as due to rounding it is not anyway possible to do 1<->1 conversion between those, regardless of what rounding is used
   
   So I wouldn't touch them now unless there is a good reason to do so (?)
   
   



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