tree 14b391392505ce5e1805160bd5480dbfe31da958
parent e66ee1a65133bfa64370d841d2b6de3e50ca376e
author Willy Tarreau <w@1wt.eu> 1612888748 +0100
committer Willy Tarreau <w@1wt.eu> 1612889570 +0100
encoding latin1

BUG/MINOR: freq_ctr: fix a wrong delay calculation in next_event_delay()

The sleep time calculation in next_event_delay() was wrong because it
was dividing 999 by the number of pending events, and was directly
responsible for an observation made a long time ago that listeners
would eat all the CPU when hammered while globally rate-limited,
because the more the queued events, the least it would wait, and would
ignore the configured frequency to compute the delay.

This was addressed in various ways in listeners through the switch to
the FULL state and the wakeup of manage_global_listener_queue() that
avoids this fast loop, but the calculation made there remained wrong
nevertheless. It's even visible with this patch that the accept
frequency is much more accurate at low values now; for example,
configuring a maxconrate of 10 would give between 8.99 and 11.0 cps
before this patch and between 9.99 and 10.0 with it.

Better fix it now in case it's reused anywhere else and causes confusion
again. It maybe be backported but is probably not worth it.