dom.ipc.processCount breaks Adblock Plus

[fanboy]

Environment

Firefox Nightly + ABP-dev on win64.

How to reproduce

1. Using Firefox nightly, set "dom.ipc.processCount" to higher value such as 8 or 12.
2. This will stop Adblock plus filters from executing properly
3. Even after a re-start of the browser, some filters won't load properly.

Observed behaviour

blocked content starts showing

Expected behaviour

Make dom.ipc.processCount work/more compatible with Adblock Plus

[diceman2037]

confirmed, this is a recent regression, less recent builds of ABP have worked with multiple webcontent processes without issue.

toggling abp after the specified amount of content processes have been spawned corrects and persists so long as the processes are not crashed or restarted.

last working
Version 2.7.3.4182-beta

broken since
Version 2.7.3.4184-beta

suggesting either
bug 4139 or bug 4162 are to blame.

https://issues.adblockplus.org/ticket/4139
https://issues.adblockplus.org/ticket/4162

[Caspy7]

Mozilla has begun to rollout "multi-e10s" (aka multiprocess with multiple *content* processes) to Firefox release users.

Initially this has been enabled for 80% of qualified users. "Qualified users" in this case means users who are already multiprocess qualified and have *no addons*. However, Mozilla will begin to expand these criteria to include more users - including users running addons.

I don't know exactly what their schedule is, but when they enable it for addon users, this bug could hit ABP users.

The initial number of content processes for Release Firefox is 4. This may go up or become users-set (in the upcoming Performance Panel) in the future.

[trev]

If anything, this issue would affect element hiding filters. I increased the process count from 4 to 8 in the current nightly but didn't notice any issues. I also don't see why a different process count should have any impact on Adblock Plus - other than maybe for the memory usage. Fanboy, this has been a while - do you still see this issue?

@Caspy7: Whatever you are seeing, it's not the issue that has been reported here. Adblock Plus has been able to deal with multiple content processes all along, the report is merely about high process counts being problematic - as opposed to the default 4 content processes. Maybe you better create a new issue and describe the problem you are seeing in more detail?

[kzar]

This seems to related to the old Firefox extension, let me know if you can still reproduce with the WebExtension extension (e.g. 3.0.2) and I'll reopen.