It could generate activity in a way that causes the GC to be run more often. Which might cause it to spend less time at each GC sweeping in the main thread? Or something? Bill or Gregor will probably have a better idea than me.
(In reply to Gregor Wagner from comment #3) > I would say the GC mode is wrong here and we perform a per-compartment GC. Ah, that would make sense! I think a bug was fixed (probably post-7) that was always displaying GCs are full even when they are compartmental. It still sounds like the triggering logic is off somehow if forcing a per-compartment GC in a tab by running an animation ends up improving the overall experience by suppressing full GCs. Per-compartment GCs would likely reduce CC time by marking everything in other compartments non-gray.
(In reply to Andrew McCreight [:mccr8] from comment #4) > (In reply to Gregor Wagner from comment #3) > > I would say the GC mode is wrong here and we perform a per-compartment GC. > Ah, that would make sense! I think a bug was fixed (probably post-7) that > was always displaying GCs are full even when they are compartmental. > > It still sounds like the triggering logic is off somehow if forcing a > per-compartment GC in a tab by running an animation ends up improving the > overall experience by suppressing full GCs. Ha that's a nice way to stop global GCs :) Incremental / parallel marking and triggering compartment GCs more aggressively will help.
Roman: have you tried reproducing this in safe mode? It could be an addon. What does your about:memory look like? It could be a leak. Marking this as P3. We have a bunch of work on the way that should improve GC and CC pause times. If it turns out there's a leak, then we can turn this into MemShrink.
I can confirm this too. Freezes of the UI takes several seconds. This happens for me after few hours of prowsing, sometimes it kaes only hour. During this time I visit about 150-200 pages and I keep about 20-30 tabs open. It started right at 3.6.4 and it is present still in 10.0.2. If you need more info contact me.
Krzysiek, could you try Nightly? Do you have any addons?
Aplikacja: Firefox 10.0.2 (20120215223356) System operacyjny: WINNT (x86-msvc) 7.0 Liczba elementów: 51 Wyłączone means disabled, Niekompatybilne means incompatible - Aardvark 3.0 (Wyłączone, Niekompatybilne) - Adblock Plus 2.0.3 - Adblock Plus Pop-up Addon 0.3 - Add Bookmark Here ² 4.0.20120221 - Add-on Compatibility Reporter 1.1 - Aero Window Title 1.6 - Anti-Banner 184.108.40.2060 (Wyłączone) - BetterPrivacy 1.68 - British English Dictionary 1.19.1 (Wyłączone) - Click to call with Skype 220.127.116.1113 (Wyłączone, Niekompatybilne) - Context Search 0.4.6 - Controle de Scripts 1.0.3 - Cookie Monster 1.1.0 - DeeperWeb for Google 1.3.3 (Wyłączone) - Download Statusbar 0.9.10 - DownloadHelper 4.9.8 - Element Hiding Helper dla Adblock Plusa 1.2.1 (Wyłączone) - Extension List Dumper 1.15.2 - Facebook Auto-Logout 0.3.2 - FEBE 18.104.22.168 (Wyłączone) - FlashGot 1.4 - Free Download Manager plugin 1.5.5 - gTranslate 0.9 - IE View 1.5.0 - Image Search Options 2.0.2 - ImageTools 1.0.4 - Is It Compatible? 0.5.3 (Wyłączone) - Kaspersky URL Advisor 22.214.171.1240 (Wyłączone) - Kaspersky Virtual Keyboard 126.96.36.1990 (Wyłączone) - MemChaser 0.2 - Memory Fox 7.4 - Multi Links 188.8.131.52 (Wyłączone) - NoSquint 2.1.5 - OperaView 0.7 - Personas 1.6.2 (Wyłączone) - Places Maintenance 1.3 - Priv3 0.11 (Wyłączone) - PrivacyChoice TrackerBlock 2.2 - QuickJava 1.7.5 - RefreshBlocker 0.8 (Wyłączone) - Replace Bookmark 1.3.8 - SearchPreview 5.3 (Wyłączone) - Session Manager 0.7.8.1 - Shareaholic 3.0.1 - Tab To Window 1.2.9 - Text Link 4.0.2011021601 - Tree Style Tab 0.14.2012021101 - UnPlug 2.050 - UpdateBookmark 0.2 - Vacuum Places Improved 1.2 - Web Developer 1.1.9 (Wyłączone) But I have made some tests with various sets of add-ons, disabling almost all of them and this produced no significinant improvement. This bug does not occur on my home computer with almost identical ann-ons (but it has XP, different Av, etc.). It also does not occur on computer of my work friend, which is identical on software and hardware level, he just uses a bit different set of add-ons. I haven't tried nightly yet, I will check it soon.
(In reply to Krzysiek from comment #9) > But I have made some tests with various sets of add-ons, disabling almost > all of them and this produced no significinant improvement. The "almost all" can be the key. Perhaps just the addon which causes the problem wasn't disabled - if the problem you see is related to addons.
I am pretty much sure that I've disabled every all add-ons in some test, and testing in dafe mode with the same results, but I can't remember for sure now. Anyway, I've tested Nightly and it behaves a bit different but not fully ok. I was testing using my profile from release FF. After some time, when memory reaches levels from 10.0.2 when hangs start to occur, it hang one time, but kept working, altough slower and some page elements start to fail loading/displaying (images). In the console I saw: http://imgur.com/Ao7eh
(In reply to Krzysiek from comment #11) > I am pretty much sure that I've disabled every all add-ons in some test, and > testing in dafe mode with the same results, but I can't remember for sure > now. > Anyway, I've tested Nightly and it behaves a bit different but not fully ok. > I was testing using my profile from release FF. > After some time, when memory reaches levels from 10.0.2 when hangs start to > occur, it hang one time, but kept working, altough slower and some page > elements start to fail loading/displaying (images). In the console I saw: > http://imgur.com/Ao7eh well, your error console logs an "out of memory" from sessionstore.js - that's pretty serious doo doo. How many tabs are open? How big is your sessionstore.js on disk in your profile? Does it definitely reproduce in safe mode?
(In reply to Andrew McCreight [:mccr8] from comment #6) > Roman: have you tried reproducing this in safe mode? It could be an addon. > What does your about:memory look like? It could be a leak. I have tried reproducing this in safe mode, and couldn't. But keep in mind that it's also not easy reproducing this in normal mode. Firefox is generally more responsive nowadays (v12) and I don't seem to have had periodic pauses due to CC/GC for quite a while. The current log seems to agree: > CC(T+67406.7) collected: 22288 (22288 waiting for GC), > suspected: 1246, duration: 51 ms. > ForgetSkippable 7 times before CC, min: 0 ms, max: 10 ms, > avg: 2 ms, total: 14 ms, removed: 621 So I suppose this bug has since gone away, presumably thanks to the work done on CC/GC on numerous other bugs. I'll make sure to post here if I see slow CC/GC again.
It is still here in newest full release. Memory keeps rising till it reaches 1.2-1.3GB - at some moment pages starts to miss loading some pictures, FF slows down to a crawl, dimms page content, GUI reactions are delayed a minute or more. After few minutes it finally crashes and closes. I am still trying to track if it some plugin or not.
(In reply to Roman from comment #13) > So I suppose this bug has since gone away, presumably thanks to the work > done on CC/GC on numerous other bugs. I'll make sure to post here if I see > slow CC/GC again. I think then we close WFM. ANd reopen if you see the problem again. Krzysiek must be seeing some other manifestation - which may be an addon
The problem has reoccurred :/ The only relevant change recently is the upgrade to Firefox 13.0 (on Win7/64). The CC times *while holding the Down arrow to scroll* are around 400-500ms, which is, of course, very noticeable. Also happening right now as I type, temporarily swallowing whole words and making Firefox feel really sluggish as a result. Logs below. (In reply to Andrew McCreight [:mccr8] from comment #6) > Roman: have you tried reproducing this in safe mode? It could be an addon. > What does your about:memory look like? It could be a leak. It's as hard to reproduce as it's always been. I restarted Firefox and it went away. I did a capture of about:memory first though; see below. I had about 20 open tabs, plus something on the order of 100 in several panorama groups, though I have them set to load on first use and most were unused. CC/GC TIMES LOG: CC(T+34.4) duration: 430ms, suspected: 2533, visited: 83205 RCed and 277925 GCed, collected: 0 RCed and 0 GCed (38 waiting for GC) ForgetSkippable 14 times before CC, min: 1 ms, max: 14 ms, avg: 2 ms, total: 39 ms, removed: 12826 CC(T+41.2) duration: 413ms, suspected: 2793, visited: 83333 RCed and 275369 GCed, collected: 0 RCed and 0 GCed (38 waiting for GC) ForgetSkippable 13 times before CC, min: 1 ms, max: 10 ms, avg: 2 ms, total: 36 ms, removed: 4574 ... GC(T+659.7) TotalTime: 137.5ms, Type: compartment, MMU(20ms): 0%, MMU(50ms): 0%, Reason: TOO_MUCH_MALLOC, NonIncrementalReason: GC mode, +chunks: 0, -chunks: 0 mark: 73.4, mark-roots: 15.0, mark-other: 9.0, sweep: 45.0, sweep-obj: 10.8, sweep-string: 4.8, sweep-script: 0.1, sweep-shape: 3.9, discard-code: 0.7, discard-analysis: 0.7, xpconnect: 9.8, deallocate: 0.0 GC(T+664.0) TotalTime: 308.6ms, Type: global, MMU(20ms): 0%, MMU(50ms): 0%, Reason: POST_COMPARTMENT, NonIncrementalReason: GC mode, +chunks: 0, -chunks: 0 mark: 237.3, mark-roots: 13.3, mark-other: 68.8, sweep: 68.1, sweep-obj: 7.0, sweep-string: 0.7, sweep-script: 1.6, sweep-shape: 12.1, discard-code: 5.6, discard-analysis: 20.1, xpconnect: 6.6, deallocate: 0.1 CC(T+670.0) duration: 410ms, suspected: 331, visited: 79834 RCed and 278508 GCed, collected: 119 RCed and 20 GCed (139 waiting for GC) ForgetSkippable 3 times before CC, min: 1 ms, max: 23 ms, avg: 8 ms, total: 26 ms, removed: 339 ... AFTER CLOSING ~10 tabs: CC(T+881.1) duration: 780ms, suspected: 2192, visited: 119549 RCed and 491483 GCed, collected: 27423 RCed and 147498 GCed (174921 waiting for GC) ForgetSkippable 2 times before CC, min: 2 ms, max: 22 ms, avg: 12 ms, total: 24 ms, removed: 257 CC(T+887.9) duration: 539ms, suspected: 109, visited: 92084 RCed and 343999 GCed, collected: 31 RCed and 14 GCed (45 waiting for GC) ForgetSkippable 3 times before CC, min: 1 ms, max: 18 ms, avg: 7 ms, total: 21 ms, removed: 177 (780ms!...) ABOUT:MEMORY Explicit Allocations 580.32 MB (100.0%) -- explicit ├──291.55 MB (50.24%) -- js │ ├───65.49 MB (11.28%) ++ (33 tiny) │ ├───52.41 MB (09.03%) -- compartment([System Principal], 0x5881000) │ │ ├──30.96 MB (05.34%) -- gc-heap │ │ │ ├──10.19 MB (01.76%) ++ objects │ │ │ ├───8.86 MB (01.53%) -- arena │ │ │ │ ├──8.66 MB (01.49%) ── unused │ │ │ │ └──0.20 MB (00.03%) ++ (2 tiny) │ │ │ ├───8.19 MB (01.41%) ++ shapes │ │ │ └───3.73 MB (00.64%) ++ (4 tiny) │ │ └──21.44 MB (03.70%) ++ (7 tiny) │ ├───38.75 MB (06.68%) -- compartment(...) │ │ ├──20.36 MB (03.51%) -- gc-heap │ │ │ ├──13.80 MB (02.38%) ++ (5 tiny) │ │ │ └───6.55 MB (01.13%) ++ objects │ │ ├──10.93 MB (01.88%) ── script-data │ │ └───7.46 MB (01.29%) ++ (6 tiny) │ ├───18.64 MB (03.21%) ── gc-heap-decommitted │ ├───18.51 MB (03.19%) -- compartment(...) │ │ ├───9.42 MB (01.62%) ++ (7 tiny) │ │ └───9.09 MB (01.57%) ++ gc-heap │ ├───14.59 MB (02.51%) -- compartment(...) │ │ ├───9.19 MB (01.58%) ++ gc-heap │ │ └───5.40 MB (00.93%) ++ (7 tiny) │ ├───13.52 MB (02.33%) -- compartment(...) │ │ ├───8.57 MB (01.48%) -- shapes-extra │ │ │ ├──8.42 MB (01.45%) ── tree-tables │ │ │ └──0.15 MB (00.03%) ++ (3 tiny) │ │ └───4.95 MB (00.85%) ++ (7 tiny) │ ├───11.52 MB (01.99%) -- compartment(atoms) │ │ ├───7.74 MB (01.33%) ── string-chars │ │ └───3.78 MB (00.65%) ++ gc-heap │ ├───11.50 MB (01.98%) -- compartment(...) │ │ ├───6.65 MB (01.15%) ++ gc-heap │ │ └───4.85 MB (00.84%) ++ (7 tiny) │ ├────9.51 MB (01.64%) ++ compartment(...) │ ├────9.04 MB (01.56%) ++ compartment(...) │ ├────7.24 MB (01.25%) ++ compartment(...) │ ├────7.21 MB (01.24%) ++ compartment(...) │ ├────7.18 MB (01.24%) ++ compartment(...) │ └────6.44 MB (01.11%) ++ compartment(...) ├──112.29 MB (19.35%) ── heap-unclassified ├──110.21 MB (18.99%) -- window-objects │ ├───83.13 MB (14.33%) -- active │ │ ├──75.87 MB (13.07%) ++ (110 tiny) │ │ └───7.27 MB (01.25%) -- top=3216 (inner=3219) │ │ ├──7.27 MB (01.25%) ++ inner-window(id=3219, uri=https://bugzilla.mozilla.org/show_bug.cgi?id=490122) │ │ └──0.00 MB (00.00%) ++ inner-window(id=3218, uri=[system]) │ ├───27.05 MB (04.66%) ++ cached │ └────0.03 MB (00.01%) ++ other ├───31.10 MB (05.36%) -- storage │ ├──29.79 MB (05.13%) -- sqlite │ │ ├──11.96 MB (02.06%) ── other │ │ ├──11.13 MB (01.92%) -- places.sqlite │ │ │ ├──10.69 MB (01.84%) ── cache-used  │ │ │ └───0.44 MB (00.08%) ++ (2 tiny) │ │ └───6.70 MB (01.15%) ++ (12 tiny) │ └───1.31 MB (00.23%) ++ prefixset ├───24.95 MB (04.30%) -- images │ ├──24.04 MB (04.14%) -- content │ │ ├──24.01 MB (04.14%) -- used │ │ │ ├──13.03 MB (02.25%) ── raw │ │ │ ├───8.51 MB (01.47%) ── uncompressed-nonheap │ │ │ └───2.47 MB (00.43%) ── uncompressed-heap │ │ └───0.03 MB (00.00%) ++ unused │ └───0.91 MB (00.16%) ++ chrome └───10.22 MB (01.76%) ++ (8 tiny) Other Measurements 2.39 MB ── canvas-2d-pixel-bytes 580.26 MB ── explicit 0.00 MB ── gfx-d2d-surfacecache 0.00 MB ── gfx-d2d-surfacevram 0.00 MB ── gfx-surface-image 12.72 MB ── gfx-surface-win32 399.96 MB ── heap-allocated 414.97 MB ── heap-committed 3.61% ── heap-committed-fragmentation 2.79 MB ── heap-dirty 38.04 MB ── heap-unallocated 10.98 MB ── images-content-used-uncompressed 7 ── js-compartments-system 115 ── js-compartments-user 160.00 MB ── js-gc-heap 4.63 MB ── js-main-runtime-analysis-temporary 44.71 MB ── js-main-runtime-gc-heap-arena-unused 0.00 MB ── js-main-runtime-gc-heap-chunk-clean-unused 0.00 MB ── js-main-runtime-gc-heap-chunk-dirty-unused 18.64 MB ── js-main-runtime-gc-heap-decommitted 0.17% ── js-main-runtime-gc-heap-unused-fraction 8.69 MB ── js-main-runtime-mjit 49.55 MB ── js-main-runtime-objects 65.17 MB ── js-main-runtime-scripts 54.68 MB ── js-main-runtime-shapes 20.81 MB ── js-main-runtime-strings 9.60 MB ── js-main-runtime-type-inference 0 ── low-commit-space-events 0 ── low-memory-events-physical 0 ── low-memory-events-virtual 628.09 MB ── private 656.64 MB ── resident 0.00 MB ── shmem-allocated 0.00 MB ── shmem-mapped 29.80 MB ── storage-sqlite 880.34 MB ── vsize 21.90 MB ── window-objects-dom 23.36 MB ── window-objects-layout-arenas 48.61 MB ── window-objects-layout-style-sets 0.04 MB ── window-objects-layout-text-runs 16.30 MB ── window-objects-style-sheets (In reply to Wayne Mery (:wsmwk) from comment #15) > ANd reopen if you see the problem again. Reopening.
It's weird, I got a dreadful bout of it the day that Firefox upgraded itself from 12 to 13 at login: by the afternoon, I was struggling to use it and eventually restarted it to stop the onslaught of freezing. I held off commenting here, and in the two days after that, it behaved normally again. Maybe the new tab page gallery feature is broken? I switched that straight off as it's of no interest to me on that computer.
Roman, could you perhaps create a CC log when the CC times are bad. https://wiki.mozilla.org/Performance:Leak_Tools#Cycle_collector_heap_dump Use the script in the first gray box. (The log may contain URLs of visited pages) zip the log and send it to me.
I'm also experiencing a lot of overall sluggishness since upgrading from 12 to 13. I'm not sure if CC is the problem here. The pauses are periodic and the didn't occur to me on v12. Win7/64, 8 GB memory Add-ons: - DOM-Inspector - Downloadhelper - LogMeIn RA plugin - Pencil - Skype (disabled) Plugins: - 2007 Microsoft Office System - Adobe Acrobat (two versions) - Google earth - Google Talk, Google Talk Video Accelerator - Google Update - iTunes application detector - Java deployment toolkit - Java platform - LogmeIn RA components - Windows Media Player plugin - Picasa - Quicktime - Shockwave flash - Shockwave for director - Silverlight - Winamp application detector (holy ****, all those plugins that are installed without you knowing!) It's pretty bad: we're talking pauses of around 1 second, perhaps more. I will upload a about:memory and CC-log in a moment.
CC-log is too big. I will send it directly to Olli Pettay as requested in #18
If you install the MemChaser addon then you can at least tell whether they are CC or GC pauses or what. https://addons.mozilla.org/en-US/firefox/addon/memchaser/
I have installed memchaser a few days ago. Both GC and CC times have been marked red after a few hours as far as I remember. GC times are currently ~750ms after a few days of surfing. CC is doing ~290ms. It looks like it also prints things to my error console, and these are the last ones I got: GC(T+224962.7) TotalTime: 742,5ms, Type: global, MMU(20ms): 0%, MMU(50ms): 0%, Reason: CC_WAITING, NonIncrementalReason: GC mode, +chunks: 0, -chunks: 0 mark: 579,1, mark-roots: 75,7, mark-other: 24,9, sweep: 159,4, sweep-obj: 12,0, sweep-string: 0,3, sweep-script: 0,4, sweep-shape: 22,5, discard-code: 1,8, discard-analysis: 6,1, xpconnect: 34,5, deallocate: 0,2 CC(T+224965.2) duration: 282ms, suspected: 59, visited: 178425 RCed and 44894 GCed, collected: 0 RCed and 0 GCed (0 waiting for GC) ForgetSkippable 6 times before CC, min: 0 ms, max: 120 ms, avg: 20 ms, total: 120 ms, removed: 1136 I will send my about:memory and this time I have a 27.8 MB big CC-log, 2.6 MB compressed so that should fit here. My previous CC-log which I sent to Olli Pettay was 161 MB uncompressed. To that, he replied (listing it here for reference): "Odd looking log. You seem to leak all the browser UI documents, 222 instances to be exact. Usually there should be no nsDocuments in the log. There are nsXPCWrappedJS (nsIObserver) objects keeping each document alive :/ Do you happen to have any addons? Can you reproduce the problem using Nightly nightly.mozilla.org?" The CC-log I'm about to submit has only two nsDocument entries so perhaps my previous log was just some hard to trigger situation and not relevant to this bug.
In addition to my previous posts, I forgot to mention that I mainly use seperate windows for browsing instead of tabs. I rarely use tabs. It's a matter of preference. I just find it easier to organise, switch between, and keep track of windows instead of tabs. Of course using windows shouldn't result in problems with GC/CC, but I may be something that helps trigger it. Sites and documents that I regularly view in my browser are google mail, google documents, youtube (with webm-format movies where possible), soundcloud (uses Flash), and several news sites. Nothing special I'd say.
This problem is still around, I have done at least one PR on it. Here is my observation. When memory usage is high enough CC's or GC's slow down, cant remember which off hand and I have just restarted firefox so wont know right this moment. this affects firefox a lot as it seems to run a cc or gc whenever loading a page. So if they are slow then the page load is slow. I have tracked down much of my memory usage to the following addons, sadly I consider them important. Tabmix plus - even tho this one is a gui plugin not one that should affect content, it adds a ton of memory usage even from when you fist open the app. Opening firefox without this addon uses approx 95meg of ram on my system, with the addon it uses 300meg off the bat. Triple the memory. since its normal for me to have 50+ tabs navigating them without multirow etc. is a real pain. tabmix plus sadly is required for me unless I find a suitable alternative. Adblock plus - A very popular plugin, this adds a ton of memory usage, I found it on average doubles my ram usage and in addition gc and cc stop working so eg. when I close tabs the memory doesnt come back if I have adblock plus loaded. Firefox devs claim to have fixed issues with this plugin but its defenitly problematic on my install. alternate ways to block ads such as requestpolicy make firefox run much faster and use much less memory but they require hand holding to allow the right requests and can mess up things like payment pages, whilst adblock plus just works. On plugins such as adobe plugin, I find these affect cc/gc performance even if they disabled, sadly I cant find a way for firefox to NOT detect these plugins, if I remove the files the respective apps automatically reinstall them as if they constantly monitoring for the presence of the plugin. I havent found a way to make firefox not scan the registry for plugins. I dont want to disable these plugins I want to REMOVE/PURGE them. Also opening new windows I found adds to memory and gc/cc demand. so 50 tabs in windows is worse than 50 tabs in 1 window. I requested a version of firefox where gc/cc is turned off, I expect if ever made it will run at lightning speed.
Please file new bugs about each issue. Hopefully with exact steps to reproduce and please tell which OS you're using. Cc me (:smaug) and :mccr8 to the bugs. Thanks. Addons change. At some point Adblock plus was working quite well. It is possible that it has changed and leaks, or Firefox has changed. Also, web sites change. Facebook was leaking like a maniac still few weeks ago. And when you say cc or gc is slow, what kind of times are you talking about? Based on telemetry data median cc time is 8ms.
The GC and CC have changed a lot in the last three years, so I'm going to mark this incomplete. The most common reason for slow CC and GC times is memory leaks. When there is a ton of stuff to look at, the CC and GC start slowing down.
And we've fixed lots of memory leaks! But if anyone sees anything suspicious, too high memory usage or high CC/GC times, please file new bugs.
Olli, what about fixing old bugs, like Bug 713216, or only new bugs get attention nowadays?
(In reply to Olli Pettay [:smaug] (high review load, please consider other reviewers) from comment #30) > And we've fixed lots of memory leaks! But if anyone sees anything > suspicious, too high memory usage or high CC/GC times, please file new bugs. (In reply to Phoenix from comment #31) > Olli, what about fixing old bugs, like Bug 713216, or only new bugs get > attention nowadays? Phoenix, I don't think Olli is saying old bug reports are always obsolete, but he is saying this bug report is :) So your question is also partly answered in comment 29. If you have a reproducible testcase, an OPEN bug report that clearly describes it should be updated, or a new bug filed for just your case.
(In reply to Wayne Mery (:wsmwk, NI for questions) from comment #32) > Phoenix, I don't think Olli is saying old bug reports are always obsolete, Actions says more than thousand words (In reply to Wayne Mery (:wsmwk, NI for questions) from comment #32) > If you have a reproducible testcase, an OPEN bug report that clearly describes it... ... that doesn't matter anything to devs, they can simply ignore it for years, as it usually happens here
It's ironic that the situation that anecdotally seems to cause the most trouble in terms of recurring periods of unresponsiveness is making use of the debugger. After all, Firebug used to cause this problem, which is why I ditched it, and why I was glad that Firefox integrated a debugger of its own. Now it seems we're slowly returning to square one. I would never want to be without all my add-ons for long enough to figure out why I still have to restart Firefox regularly due to what I guess is still the same problem. In 64-bit Firefox (which I run at home in Windows 10 now that it's finally become available) it would seem more practical to me to care less about garbage collection and more about responsiveness -- after all, I only run 64-bit Firefox to stop it crashing after hitting 2 GB RAM. There's less value in collecting garbage since it's got as much virtual memory as it could dream of. Also, surely it could collect garbage when every window is inactive? If I'm using other software, that's a good time to for Firefox take a long hard look at the RAM, instead of when I'm trying to watch a video or scroll through a page. GC cycles that run during scrolling are the most idiotic. With that said, it's a waste of time. I still don't understand why Firefox gobbles up RAM so fast. The about:memory features do little: Firefox and/or addons just won't let go of so much rubbish in RAM, so running continual GC cycles seems senseless as you're never getting that RAM back no matter how many times you beg the heap to let go of its unused objects. Generally the only time you ever see RAM released is directly after closing a tab with large images, and it releases the RAM the images took. The rest of it is just lost. All browsers now eat RAM like there's no tomorrow, and I have no idea why. Firefox is the worst hit as it's effectively single process (for now anyway), while other browsers keep spawning more RAM-chugging processes and can avoid hitting 1.5 GB limit in any one process. Looking at the about:memory figures never told me anything: all the memory is just in use by everything. In 32-bit Firefox it's a toss-up regarding whether I have to restart it due to constant freezes as it fights to save its life as it butts up against the 1.5 GB limit, or whether it's freezing too often. Normally the RAM runs out. Sometimes so much so that it crashes on exit, but normally it only gets to the screaming in pain stage before I safely restart it. </rant>