• Nils Goroll's avatar
    Parameter ban_cutoff to limit the number of active (incomplete) bans · 4073a4b6
    Nils Goroll authored
    Expurge long tail content from the cache to keep the number of bans
    below this value. 0 disables.
    
    This is a safety net to avoid bad response times due to bans being
    tested at lookup time. Setting a cutoff trades response time for cache
    efficiency. The recommended value is proportional to
    rate(bans_lurker_tests_tested) / n_objects while the ban lurker is
    working, which is the number of bans the system can sustain. The
    additional latency due to request ban testing is in the order of
    ban_cutoff / rate(bans_lurker_tests_tested). For example, for
    rate(bans_lurker_tests_tested) = 2M/s and a tolerable latency of
    100ms, a good value for ban_cutoff may be 200K.
    
    Merges #2131
    4073a4b6
cache_ban_lurker.c 10 KB