The timer_create() system call is not supported in ESX and returns
an error when called. Aborting when this system call fails seems a
bit extreme. So instead, this patch simply falls back to disabling
the cached time optimization.
Signed-off-by: Ethan Jackson <ethan@nicira.com>
64-bit Linux appears to avoid syscalls for clock_gettime(), so we can get
higher resolution timing and avoid having a timer firing off SIGALRM
without introducing extra overhead.
Signed-off-by: Leo Alterman <lalterman@nicira.com>
Replaced all instances of Nicira Networks(, Inc) to Nicira, Inc.
Feature #10593
Signed-off-by: Raju Subramanian <rsubramanian@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
An upcoming commit has a new use for the time at which OVS started up, so
this moves this functionality to a common location.
Signed-off-by: Ben Pfaff <blp@nicira.com>
This is a necessary prerequisite for allowing time to be "fast forwarded"
in unit tests, to keep tests that depend on the passage of time from
running in real time. Without this change, a code sequence like this:
poll_timer_wait(1000);
...fast forward time 5 seconds...
poll_block();
would still sleep for a second, because the poll_loop module would still
have a relative timeout of 1000 ms.
Signed-off-by: Ben Pfaff <blp@nicira.com>
For a long time, the poll-loop module has had the ability to log the reason
for wakeups, which is valuable for debugging excessive use of CPU time.
But I have to ask users to turn up the log level for the module, which
wastes their time and mine. This commit improves the situation by
automatically logging the reason for a wakeup whenever a process's
estimated CPU usage rises above 50%. (ovs-vswitchd often uses less than
1% CPU; more than 5% CPU is uncommon.)
Since the timeval module now initializes itself on-demand, there is no
longer any need to initialize it explicitly, or to provide an interface to
do so.
Most of the timekeeping needs of OVS are simply to measure intervals,
which means that it is sensitive to changes in the clock. This commit
replaces the existing clocks with monotonic timers. An additional set
of wall clock timers are added and used in locations that need absolute
time.
Bug #1858
Without removing SA_RESTART from the SIGALRM handler, the fcntl call will
never return, even after the signal handler is invoked and returns.
We haven't seen a problem in practice, at least not recently, but that's
probably just luck combined with not holding the configuration file lock
for very long.
Open vSwitch uses an interval timer signal to tell it that its cached idea
of the current time has expired. However, this didn't work in a daemon
detached from the foreground session (invoked with --detach) because a
child created with fork() does not inherit the parent's interval timer and
we did not re-set it after calling fork().
This commit fixes the problem by setting the interval timer back up after
calling fork() from daemonize().
This fix is based on code inspection (which was then verified to be correct
through testing). It may not fix any actual problems in practice, because
time_refresh() is called every time through the poll loop, and the poll
loop typically runs more quickly than the periodic timer fires (1 ms or so
average in ovs-vswitchd, vs. 100 ms timer interval).
