Hi,
I am on VPP 18.01.
I see the following while loop in the
vlib_worker_thread_barrier_sync_int function
(src/vlib/threads.c)
while (*vlib_worker_threads->workers_at_barrier != count)
{
if ((now = vlib_time_now (vm)) > deadline)
{
fformat (stderr, "%s: worker thread deadlock\n", __FUNCTION__);
os_panic ();
}
}
Suppose I have 4 workers (and 1 main thread), so the value of count will be 4.
Each worker bumps up the workers_at_barrier by 1.
So if the while loop in its sampling misses seeing the value bumping
by the third worker, and the 4th worker bumps up the value, then
workers_at_barrier will become 5 and the while will never break
eventually missing the deadline.
I am seeing this happening occasionally on some of my setups.
Do you think it is safe to change the while like this instead ?
while (*vlib_worker_threads->workers_at_barrier <= count)
Regards
-Prashant
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