Firefox 69 to use Process Priority Manager

Martin Brinkmann
Jun 2, 2019
Firefox
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37

Mozilla plans to enable a new feature called Process Priority Manager in Firefox 69 Stable later this year. The organization began to integrate the feature in Firefox Nightly about a year ago and has tested it thoroughly in that time.

The idea behind the feature is to deprioritize background tabs open in the Firefox browser so that the active tab (foreground tab) may have additional resources at its disposal. Firefox's new process priority management feature won't impact background media processes as playback quality might suffer otherwise.

Firefox will give Windows hints to appropriately set content process priority levels, meaning more processor time spent on the tasks you're actively working on, and less processor time spent on things in the background (with the exception of video and audio playback).

Process Priority Manager is already enabled in Firefox Nightly. The feature is controlled by a preference that users of the browser may change to enable or disable it. The preference will be available in all versions of Firefox; while it is generally not recommended to disable the Process Priority Manager, some may need to do so if they run into issues when it is enabled on their devices.

Mozilla ran some tests and concluded that the "process priority manager had no measurable impact on page load time, tab switch time, or user retention". The organization's test did not make things better, however, in test scenarios either.

It is possible, however, that the results may be positive in low resource environments.

Do this to change the value of the Process Priority Manager:

  1. Load about:config in the Firefox address bar.
  2. If the warning prompt is displayed (it is on first use and afterward if you don't disable it), accept it.
  3. Search for dom.ipc.processPriorityManager.enabled.
  4. Set it to True if you want the feature enabled and set it to False if you want to disable it.

Firefox 69 is scheduled for a September 3, 2019 release. (via Techdows)

Summary
Firefox 69 to use Process Priority Manager
Article Name
Firefox 69 to use Process Priority Manager
Description
Mozilla plans to enable a new feature called Process Priority Manager in Firefox 69 Stable that prioritizes foreground over background tabs.
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Ghacks Technology News
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Comments

  1. Anonymous said on September 10, 2019 at 4:01 pm
    Reply

    This feature is causing WhatsApp Web (which I use a lot) to disconnect when the tab is in the background, I guess it doesn’t give enough CPU time to background tasks and the connection times out.

    Disabling it in about:config fixed it.

    1. Anonymous said on March 7, 2020 at 5:35 pm
      Reply

      Update: It didn’t fix it, WhatsApp “overloads” when the chat history is too big, I deleted all of it and now it works fine again.

  2. owl said on June 11, 2019 at 8:51 am
    Reply

    This topic,
    Process Priority Manager is already enabled in Firefox Nightly. The feature is controlled by a preference that users of the browser may change to enable or disable it. The preference will be available in all versions of Firefox

    I was interested in “Process Priority Manager”, so I checked it in my “DeveloperEdition 68.0b7 (64-bit)” version.
    However, dom.ipc.processPriorityManager does not exist in about: config.
    It seems to be a topic in the “Nightly” version.
    https://bugzilla.mozilla.org/show_bug.cgi?id=1548364
    https://hg.mozilla.org/mozilla-central/rev/79a4c6547690

  3. OzMerry said on June 3, 2019 at 3:12 pm
    Reply

    I’ve been using the add-on Auto Tab Discard for that.

  4. Anonymous said on June 3, 2019 at 1:03 pm
    Reply

    “Mozilla ran some tests and concluded that the “process priority manager had no measurable impact on page load time, tab switch time, or user retention”. The organization’s test did not make things better, however, in test scenarios either.”

    what the…

  5. John C. said on June 3, 2019 at 9:43 am
    Reply

    My question is: what if I open several tabs at once? Will the background tabs only load when I open them?

    Otherwise, I’m gun-shy on this one. Mozilla has a history of making a “feature” enabled by default but still optional via about:config, then deactivating the preference, then removing the preference and VOILA now everybody has to accept the change, like it or not.

    If Process Priority doesn’t really improve anything, then why are they doing this? I smell a dead rat.

  6. ddk said on June 3, 2019 at 6:26 am
    Reply

    On a previous posting I mentioned a site called “venturesky” it’s actually ventusky.com, an animated weather site not working in FF….sorry for the confusion..

    1. Fuzzi said on June 3, 2019 at 3:17 pm
      Reply

      @ddk
      I also cannot confirm. Loads and works instantly in FF67.0 here.

    2. AnorKnee Merce said on June 3, 2019 at 9:24 am
      Reply

      @ ddk

      My Firefox 60 ESR has no problem with ventuskydotcom. Nice wx site.

  7. ddk said on June 3, 2019 at 4:29 am
    Reply

    I decided to retry FF after about a years absence, compared to Chromium it is SLOW, sometimes as molasses. Very apparent on sites like Weather Underground, loading maps took a long time. Animated sites like Venturesky and Windy TV flat out don’t work, those sites are broken on FF.

    It might be lack of Flash built in like Chrome has but not wanting to install that, forget about the many sites including government portals that still use it. FF at least should accommodate a pepper flash plug-in, some of the reasons many switched to other browsers over the years.

    Thought I’d try it out pending the manifest changes coming to Chrome. I hope GOG backs away from that.

    1. Anonymous said on June 3, 2019 at 1:21 pm
      Reply

      I suppose “Windy TV” is windy dot com. Just checked that one as well and it, too, loads instantly on FF 67 w/ flash disabled. The problem lies on your end, not in Firefox.

    2. Anonymous said on June 3, 2019 at 1:18 pm
      Reply

      I checked and both ventusky and Weather Underground load instantly on Firefox 67 with flash disabled. Thus it must be your configuration and/or hardware and/or connection causing your problem. Correlation does not necessarily imply causation.

  8. Yuliya said on June 3, 2019 at 4:07 am
    Reply

    Now your telemetry process can run in high priority, lmao.

  9. James said on June 3, 2019 at 2:07 am
    Reply

    For the record, such a feature will never make it in Palemoon… I’ll leave this here.

    1. Ascrod said on June 3, 2019 at 5:14 pm
      Reply

      Process prioritization doesn’t mean anything if your browser uses only one process by design.

    2. Bobby Phoenix said on June 3, 2019 at 5:50 am
      Reply

      True. Palemoon doesn’t have the developers or resources to keep up with Mozilla, but Palemoon is still a great browser if you want to use a fork of Firefox.

    3. Yuliya said on June 3, 2019 at 3:54 am
      Reply

      You don’t need it anyway. The OS knows which processes to prioritise based on what you use. It’s a feature enabled by default on client Windows and disabled on server editions, but available for you to toggle on or off at your will.
      If you, however, consider the OS is not doing a good job, you can manually orride it from task manager.
      imgur.com/TbEpXjH

      1. Ali said on June 6, 2019 at 12:08 pm
        Reply

        because firefox uses a content process for several tabs, OS can’t know what tab you use to manage the memory better than firefox.
        firefox should manage it itself.
        also chrome does this and is far better that firefox in memory management in my system.

  10. Franck said on June 3, 2019 at 12:41 am
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    It’s a good idea, thanks for the news Martin !

  11. dante said on June 2, 2019 at 10:21 pm
    Reply

    Well Google just “accidentally” made Gmail and Youtube not work on Firefox again. Time to find a company that actually doesn’t Do Evil.

  12. K@ said on June 2, 2019 at 6:44 pm
    Reply

    I dumped Firefox. On rare occasions, I use SeaMonkey and that seems much better, to me. The last few thousand “improvements” they made have made it worse, each time. It’s so bloated, now. I can’t be doing with it, at all.

  13. user17843 said on June 2, 2019 at 2:49 pm
    Reply

    The engineer on bugzilla wrote:

    “So, the good news is that it doesn’t appear to make things worse”

    They can’t be serious. The jokes write themselves with Mozilla these days.

    1. John C. said on June 3, 2019 at 9:49 am
      Reply

      Where was that said? Which bug? Were you joking or did this actually happen? TIA

      1. Anonymous said on June 3, 2019 at 3:00 pm
        Reply
      2. user17843 said on June 3, 2019 at 2:27 pm
        Reply

        It was said by the lead engineer for this task (Mike Conley) in the first link of the above article: https://bugzilla.mozilla.org/show_bug.cgi?id=1548364

      3. Anonymous said on June 12, 2019 at 6:35 pm
        Reply

        Care to add the very next paragraph? No, of course:

        “We do know, however, that lowering background tab process priority allows the OS to prioritize work in foreground tabs. So at the very least, this should be a resource usage win.”

        Trolling here (or at MozillaZine or every other Mozilla-related forum) has become really tiresome. I will miss Martin’s, Pants’ and Tom Hawack’s posts; gotta keep an eye on things elsewhere.

      4. Tom Hawack said on June 12, 2019 at 9:37 pm
        Reply

        You can continue to read Ghacks’ articles without reading the comments or even without commenting yourself, a way to move back in the flock and recover. That’s my choice. I read as I used to these great articles but don’t comment any longer; I do read comments nevertheless if the first words let me hope no troll or repetitive wording all of bashing stereotypes are not ahead.

        As you maybe I’m tired, never of the articles which remain splendid IMO, but of some comments which appear to me as (un)merry-go-rounds. too many of them. The worst is that I surprised myself sometimes joining a yelling crowd, when I’m not like that in life. I’ve always been a misanthrope anyway.

        But Ghacks continues, fortunately! And I visit several times a day. But silently from now on. Besides, I have so little to say pertaining to technology and too frequently slipped towards pseudo-philosophical considerations.

        Maybe one day I’ll jump back in the arena. But for now I need a good rest.

  14. Klaas Vaak said on June 2, 2019 at 10:39 am
    Reply

    If it has no impact on regular computers but only useful on low resource ones, why not set it as a toggleable option, rather than as a default setting?

    1. John Fenderson said on June 3, 2019 at 5:12 pm
      Reply

      @Klaas Vaak:

      Or, even better, have the browser detect the speed and available resources of the machine it’s running on when it starts and set the default according to what it finds.

      1. Klaas Vaak said on June 4, 2019 at 4:55 pm
        Reply

        @John Fenderson: that would be ideal, of course, if it is possible.

      2. John Fenderson said on June 4, 2019 at 6:39 pm
        Reply

        @Klaas Vaak:

        It’s certainly possible from a technical point of view. All sorts of software does this sort of thing routinely. As to whether there’s an architectural issue with Firefox that makes it difficult for Firefox to do this, I can’t say.

    2. bwat47 said on June 3, 2019 at 3:38 pm
      Reply

      If it has no negative impact, what is the point of allowing it to be toggled off?

      1. Klaas Vaak said on June 4, 2019 at 4:58 pm
        Reply

        @bwat47: because there’s no point to add things that don’t add value for the users and add bloat instead.

    3. Marco said on June 2, 2019 at 3:24 pm
      Reply

      Because the majority of users wouldn’t know how to turn it on.
      Or perhaps Firefox is doing it just to annoy you.

      1. Klaas Vaak said on June 4, 2019 at 4:56 pm
        Reply

        @Marco: still not a reason not to do it. The majority of users don’t know how to use about:config either.

    4. That one guy said on June 2, 2019 at 3:18 pm
      Reply

      This^

      1. Klaas Vaak said on June 4, 2019 at 4:56 pm
        Reply

        @That one guy: ?

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