aboutsummaryrefslogtreecommitdiff
path: root/doc/threads.texi
diff options
context:
space:
mode:
Diffstat (limited to 'doc/threads.texi')
-rw-r--r--doc/threads.texi26
1 files changed, 26 insertions, 0 deletions
diff --git a/doc/threads.texi b/doc/threads.texi
index 6dd2226..3219f2d 100644
--- a/doc/threads.texi
+++ b/doc/threads.texi
@@ -52,3 +52,29 @@ configuration file statement (@pxref{daemon, max-connections}).
Processes a triplet. A separate thread of this type is started by
@samp{WY_listener} for each valid triplet it detects.
@end table
+
+@menu
+* Event timestamps in WY_stat::
+@end menu
+
+
+@node Event timestamps in WY_stat
+@unnumberedsec Event timestamps in WY_stat
+
+On GNU/Linux systems the events generated by the @samp{WY_stat} thread
+may appear to happen one second prior to their scheduled time. This
+happens if the software reporting the events uses @code{time}(2)
+instead of @code{gettimeofday}(2) for time reporting. The internal
+timekeeping mechanism of the linux kernel is designed so that the
+number of seconds returned by @code{time} may be one less than the
+@code{tv_sec} value after return from @code{gettimeofday}, if the two
+functions would be called the same instant@footnote{See
+@uref{https://stackoverflow.com/questions/22917318/time-and-gettimeofday-return-different-seconds},
+for details}.
+
+The two known cases are the legacy @command{syslogd} used by default
+on Slackware systems, and the @command{Sendmail} MTA.
+
+Since the results returned by @code{gettimeofday} are more accurate,
+it was decided to leave this feature as it is, instead of installing
+workarounds of dubious nature just to satisfy older software.

Return to:

Send suggestions and report system problems to the System administrator.