> On 25 Sep 2018, at 11:27, Olivier Hanesse <[email protected]> wrote: > > Hello Carlos, > > Thanks for your answer. About thread contention during invalidation, can you > be more specific ? > At what scale can we encounter such contentions ? > Hundreds of objects linked to a key ? or Thousand ? ten thousand ?
Hi Olivier, Basically I'm talking about thread contention generated by this loop [1]: when a key is purged, if that key is linked to a huge amount of objects, the lock is going to be held during a noticeable amount of time. That will block other threads executing callbacks [2] in order to to add / remove object to / from the xkey state. What would be too many objects linked to a single key? To be honest, I don't know. For an answer we'll need to invoke the VMOD authors :) [1] https://github.com/varnish/varnish-modules/blob/0.15.0/src/vmod_xkey.c#L531-L579 <https://github.com/varnish/varnish-modules/blob/0.15.0/src/vmod_xkey.c#L531-L579> [2] https://github.com/varnish/varnish-modules/blob/0.15.0/src/vmod_xkey.c#L423-L465 <https://github.com/varnish/varnish-modules/blob/0.15.0/src/vmod_xkey.c#L423-L465> Best, -- Carlos Abalde
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