?impact: identical filter rule in multiple subscriptions

[Wisdom Fluxion]

Will this have more than a negligible impact on performance?

Additionally which filter is credited a 'hit'?

[Ares2]

If it's exactely the same filter, it's treated as one filter by ABP -> no performance impact and same hitcount.

[Wladimir Palant]

For Adblock Plus it is really the same filter even though it shows up multiple times in the list. Consequently, hit counts are consistent throughout all occurrences of that filter and there is no performance impact.

[Adblock Plus Fan]

identical filter rule in multiple subscriptions

For identical filters, it is as Wladimir and Ares said.

But in practice, there's a likelihood that similar filters will be made just slightly different. Perfect example: http://adblockplus.org/forum/viewtopic. ... 3108#23108
(That post and the few posts prior to it)
Two filter subscriptions fight over the same optimising shortcut "/468x60/". Only one filter can have that shortcut, and so you will have performance penalty since these shortcut conflicts can cause more unoptimised filters to be made.