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Comment by ericabiz | Hacker News Reader

Agreed. Now: does Mozilla read these?

I tried to switch to Firefox, but was stymied by a bug where Firefox consumes 100%+ CPU on MacBook Pro Retinas.

Firefox is basically unusable with this bug; Facebook takes forever to load, and even Reddit r/firefox shows "A webpage is slowing down your browser" bar at the top.

Active relevant bugs are here: https://bugzilla.mozilla.org/show_bug.cgi?id=1404042 https://bugzilla.mozilla.org/show_bug.cgi?id=1429522

But apparently this has been going on for 2+ years and Mozilla hasn't been able to fix it.

Given rMBPs (I would think) would be a fairly large market share of people who work at Mozilla or use Firefox, it's both concerning and surprising that a bug of this proportion has gone on so long.

Edit: Jeff from Mozilla has reached out. I sent him a perf log and a screenshot. Tracking here: https://bugzilla.mozilla.org/show_bug.cgi?id=1494186

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Neither of those bugs have to do with 100% CPU on rMBP. Their about using an inefficient presentation path which increases GPU power usage. You can mitigate this today by setting gfx.compositor.glcontext.opaque to true. Further, Firefox Beta has additional texture upload performance improvements that will reduce cpu usage.

If you're actually experiencing 100% cpu usage, post a profile using https://perf-html.io/ and I can try tell you why.

Steps to reproduce:

1) Pick a rMBP. Any one.

2) Set display options - "more space" under System Preferences.

3) Run Firefox. Load any website. No extensions; safe mode doesn't matter.

4) 100%+ CPU, fans kick up and run high, system gets hot and slows to a crawl.

Chrome and Safari run totally fine under the same conditions.

It's documented pretty thoroughly in the first Bugzilla link I posted; the second one is an offshoot where they're trying to solve this specific issue. If you do happen to work at Mozilla, would really appreciate your help escalating.

EDIT: I now have a perf file showing significant issues when clicking on a YouTube video. It gives an error when trying to upload it to the site, but if you contact me through email (in my HN profile), I can send it over.

I don't have a rMBP, and others who may be curious to help may not either. Uploading performance profiles from various websites to the mentioned URL will give everyone something to poke at.

I spent a few minutes trying to replicate on a MacBook Pro (Retina, 13-inch, Late 2013) with Firefox 62.0.2 and could not replicate, browsing a number of resource intense sites.

Interesting, as this is the same MBP I have, and same Firefox version. I now have a perf file showing the issue. Can't upload it (it gives an error), but would be happy to send it to anyone who thinks they can help.

You can send it to me at jrmuizel@mozilla.com

I'm on Mac OS 10.11.6 (15G22010). The regression might be due to some interaction between Firefox and changes in the OS, if you're on a more recent version.

I've been doing this since the first-gen rMBP, and I've never had this issue. No matter my scaling, I idle at about 5% CPU with about 80 tabs and 10 windows actively open.

Can't reproduce that here (on either of two different machines)-- something else may be going on on your machine.

I'm not sure what it is with your MBP but my Firefox does the same thing anytime I open a phys.org page -- one Firefox at work using Ubuntu 16.04 and the other at home using Windows 7 both exhibit it.

Edit: Actually I just checked and the Windows 7 machine doesn't do it any more. I'm not sure if maybe a Firefox update fixed that here. I'll double check at work tomorrow too

1) I'm running a MacBook Pro (Retina, 15-inch, Mid 2015)

2) My display options are set to "more space"

3) I loaded this hackernews thread.

4) Firefox and it's child processes are using <1% cpu.

If I aggressively scroll this page I can push the cpu usage up. We have a variety of fixes in the pipeline that will help with this (https://bugzilla.mozilla.org/show_bug.cgi?id=1429522, https://bugzilla.mozilla.org/show_bug.cgi?id=1265824). That being said, only 4.7% of our users are on MacOS so it's more difficult to justify prioritizing work specific to that platform.

4.7% of your users, but what percentage of web developers?

If that second number is substantially higher (and I personally suspect it is, but I don't have data backing that up) I think it would be very reasonable for Mozilla to prioritize MacOS. Getting web developers to use firefox makes firefox work better for everyone because it makes more sites work well with firefox.

Yeah, we do prioritize Mac disproportionately to its market share for that reason. It does sometimes happen that we have to make hard calls though, and that's what Jeff is referring to.

On that note, one of the key motivators behind WebRender (our new graphics backend) is that it provides hardware acceleration across all platforms, including mac (whereas our current Direct2D acceleration works only on Windows). So Mac graphics performance should generally improve once we get that shipped.

First off, thank you for all of your hardwork. I'm grateful for the existence of Mozilla.

However, I would like to ask... 4.7% translates to how many millions of people?

4.7% of your users... and how much of that is because you are finding it difficult to prioritise work specific to that platform? It sounds like a chicken-and-egg problem to me.

Now don't get me wrong: I'm a big fan of Firefox, and have used the dev edition as my main work browser since Quantum came out. However, that's a terrible attitude to take. You have half a billion dollars per year of revenue. The second-largest desktop platform should be a major priority. Certainly above all of the other non-core-Firefox projects you're working on, however cool they may be.

I build internal tools in my organization. Most of our developers are on MacOS and use Chrome day to day. Most of our users are on Windows. Whenever a browser specific issue comes up, we do our best to address it, but our first response is typically "go install Chrome". Chrome adoption is 97% internally, 2.5% Safari, and the remaining 0.5% is Edge. We have a 0% internal Firefox usage rate.

Draw from that what you may, but I bet that dynamic is happening in other places.

I also have this problem, and it's a reason not to use Firefox for me. Maybe you only have 4.7% of users on MacOS precisely because of problems like these?

All I have to do is load gmail and it'll hit over 100% CPU in top. Usually between 125% and 175%. http://bit.ly/2QaGqzJ

That profile shows all of the time being spent in script execution. Are you sure that setting a different resolution has a dramatic effect on the amount of CPU being used?

Nope. I'm not the Retina Mac person. I'm gonna guess a lot of sites make the system busy with scripts, they all post 100+% CPU loads, fans go on, system gets warm - just to load them. Every once in a while the go nuts well after loading and I'll see a Web Content process over 100% and just stay there but I don't know which tab is causing the problem, so I usually end up killing the whole browser.

I don't know exactly what conditions are required to reproduce the bug, but it clearly does not apply to all rMBPs. I'm on a 15-inch 2016 rMBP and have been using Firefox on it successfully since I got it. Before that I spent a couple months on a 2013 rMBP, also no problems.

Edit: For people who want to compare notes: High Sierra 10.13.6, Firefox 62.0.2, resolution is set to "Default for display" (which I think does mean it's doing interpolation of some sort). Automatic graphics switching is enabled. I don't have any trouble watching YouTube videos.

It happens when you set your rMBP display to "Scaled" in display preferences, which is what most developers do. (Edit to your edit: Try the "More Space" option in your display preferences! It's amazing.)

I tried this as well, can't reproduce.

I've got a 15" "late 2013" rMBP, set display options to "more space." I've got a total of 45 tabs open between a couple different windows (I use the userChrome hack to re-enable multiple tab rows.) Cycled between tabs, refreshed, navigated around FB, GMail, etc. Can't get the CPU to do anything out of the ordinary.

Similar to the sibling comment, I can't seem to repro. I switched "More Space", restarted Firefox, loaded up a dozen or so tabs. I even watched a YouTube video for about 10 minutes. The video did cause CPU to jump a bit, but it dropped when I unloaded the tab, and nothing I've done (including the video) has caused any sort of lag like described in your first post or subsequent follow-up.

I'm not sure what to say. I'm sure the issue is real, but it seems like we're missing something in the triage. There has to be something else that makes a difference.

I very much doubt that “most” developers use “More space”.

Most developers in their early 20s seems plausible, but even there, I surveyed my team’s younger cohort, and it was less than 50%.

I have my display set to "scaled". I get the worst slowdown when streaming videos. 2013 15" w/ Nvidia gpu.

That is why I switched from Chrome to Safari for the daily driver, and Firefox for webdev stuff only

> I tried to switch to Firefox, but was stymied by a bug where Firefox consumes 100%+ CPU on MacBook Pro Retinas.

On the flip side, I've had a recurring bug in Chrome (until very recently) where for any long running session the Browser process will consume 100% of 1 core. I've had it across multiple machines and profiles, including a completely clean profile with no extensions - I've never managed to be able to nail down the common elements.

With my 2012 rMBP (first gen retina, with nVidia GT 650M) I cannot play video on various websites using Firefox since about a year or two. Did an OS reinstall, switched to nVidia native drivers, nothing helps. It plays the first second of video, then freezes, audio does continue. Youtube does work, but performance is poor.

> Given rMBPs (I would think) would be a fairly large market share of people who work at Mozilla or use Firefox

Why?

I just tried this.

Firefox with one tab (with gmail opened) takes 20% CPU. (and a helper process "FirefoxCP Web Content", which takes 50% CPU, wow.)

Chrome with some 20 tabs, ~4-5% with all its processes (but a lot of ram, which I am fine with)

This is for a 2015 13-inch Macbook pro.

It’s a bit ironic you use Facebook but won’t use Chrome.

Facebook is super relevant for our business. Not only do we advertise on there, but I also sit on Messenger and answer computer and phone repair questions from friends, and get tagged in "Help! My computer stopped working" types of posts. It drives good business to our repair shops.

Facebook has also replaced forums for our industry (cell phone/computer repair), so it's how we find out about the latest trends and innovations. Yesterday I used a document posted on a private FB group to fix 3 2011 15" MacBook Pros with failing GPUs (previously considered "unfixable.")

For the industry and business I'm in, there's no substitute.

That's interesting. I would have assumed that Reddit was a much better resource for at least the technical docs. Many subreddits include a crazy amount of very specific information about just about anything you can think of.

Totally agree in general; I've gone down the "Reddit rabbit hole" almost too many times to count.

Private groups on FB can be more discerning about their membership, which is also what makes them interesting.

Many of the cell phone repair groups I'm in require you to have a repair business, so the groups don't get flooded with what they call "plz bro" posts. (i.e. "How do I fix an iPhone screen?" beginner posts.)

It also forms a tighter community; we pretty much all know each other on there, so we refer business back and forth a lot, and use Messenger heavily to buy, sell, and just chat about really obscure or weird repairs that come in the door.

I use Facebook very occasionally, and when I do I use Firefox with containers enabled. Facebook and related sites get their own containers.

It seems that nowadays Mozilla is interested in PR much more than the Firefox browser. Every other day, there is some announcement or the other.

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