1066789 - Implement a heuristic to replace dom.ipc.processCount

Status: RESOLVED INCOMPLETE

(Core :: DOM: Content Processes, enhancement, P3)

Description

[(not currently active) Ted Mielczarek]

Currently to get more than one content process you set dom.ipc.processCount to a number >1 and we create a new process for each tab until we create that many processes.

We should have a heuristic based on the total memory and cpu cores available in the user's machine that we can use to replace this for desktop. I suggest something like:
processCount = min(availableMemory / kPerProcessMemoryOverhead, availableCPUCores * kMaxProcessesPerCore)

Where availableMemory and availableCPUCores are derived from system information, and kPerProcessMemoryOverhead and kMaxProcessesPerCore are constants that we decide on.

b2g wants this to be "unlimited":
http://hg.mozilla.org/mozilla-central/annotate/6a8b7740dc53/b2g/app/b2g.js#l420

so we either need to provide them an opt-out, or make this a special-case, by having dom.ipc.processCount==0 enable this heuristic.

Comment 1

[(not currently active) Ted Mielczarek]

ContentParent manages the pool of content processes:
http://hg.mozilla.org/mozilla-central/annotate/6a8b7740dc53/dom/ipc/ContentParent.cpp#l783

Comment 3

[u595893]

will there be an option to disable this and just use a user value, ipc =1 is what works on my machine , anything above it kills the performance on my dual core

Comment 4

[Jeff Griffiths (:canuckistani) (:⚡︎)]

(In reply to shellye from comment #3)
> will there be an option to disable this and just use a user value, ipc =1 is
> what works on my machine , anything above it kills the performance on my
> dual core

Yes.

Comment 5

[intrigeri]

FWIW in Tails we had to decrease dom.ipc.processCount to 2 on systems with less than 3GB of RAM when upgrading to Tor Browser 8 i.e. Firefox 60 ESR, due to increased memory usage that was excessive for lower-spec'ed systems.

Comment 6

[avada]

(In reply to intrigeri from comment #5)
> FWIW in Tails we had to decrease dom.ipc.processCount to 2 on systems with
> less than 3GB of RAM when upgrading to Tor Browser 8 i.e. Firefox 60 ESR,
> due to increased memory usage that was excessive for lower-spec'ed systems.

Tell me about it. With a 48 limit I sometimes get 20+ gigabytes freed when I close a bunch of tabs.

Comment 7

[Jens Stutte [:jstutte]]

Hi Olli, is this still relevant post-e10s and post-fission ?

Comment 8

[Olli Pettay [:smaug][[e-mail]]]

Fission changes this all, no need to track this.