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Firefox engineers discover a Windows Defender bug that causes high CPU usage

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Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#201

Post by nikanj »

elygre wrote: post #194
nikanj wrote: post #184

Earlier quoted context omitted.

The biggest surprise for me was Microsoft actually fixing it.

Is that because you don't expect programmers in general to fix their bugs? Or do you think Microsoft in particular don't care about their products?

Because once a corporation grows larger than some singularity threshold, there seems to be a bug event horizon where all bug reports just disappear.

Send a bug report to a five-person software company, their lead dev contacts you the same day and has a patched version ready to go in a week. Send a bug report to Microsoft / Citrix / Apple / etc, and you'll never hear back.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#202

Post by rejectfinite »

psychphysic wrote: post #31
IronWolve wrote: post #27

Earlier quoted context omitted.

It's not just mozilla, been working defender issues for the last few years on thousands of windows vm's. Mostly due to the enabling the more intensive heuristic real time engine and they have different code bases depending on versions installed on different windows builds, and patching does seem to trigger it. For months we had issues where we couldnt log into some vm's due to high cpu for defender, and had to bounce…

I have malwarebytes premium and defender CPU usage is nearly 100% at times bringin Firefox to a halt. Chrome works fine..I've been blaming Firefox so far.

I am on Windows 10, Malwarebytes premium and using Firefox Nightly on Youtube right now and it is using miniscule CPU and has so for a long time. On a i7 4790k desktop machine.

Firefox itself is at 4-5% and the whole machine is at 14%

Normal Firefox was also fine last I used it.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#203

Post by maccard »

Yoric wrote: post #85
psychphysic wrote: post #31

Earlier quoted context omitted.

I have malwarebytes premium and defender CPU usage is nearly 100% at times bringin Firefox to a halt. Chrome works fine..I've been blaming Firefox so far.

In my experience (as a former Firefox dev), antivirus / antimalware software are really poorly behaved. They tend to: - require admin rights (which means that if they have vulnerabilities, it can take control of the entire machine, even if Firefox itself is sanboxed); - monkey-patch the Firefox executable in memory, which works (when it does) as long as the version of the software tracks closely the version of Firefo…

> Part of the work on Crash Scene Investigations was attempting to determine whether the crash was in Firefox or in code or in some bogus foreign code. Depressingly often, it was the latter.

A shockingly large number of crashes and performance issues in PC gaming are related to poorly behaved overlay programs and overclocking tools like RivaTuner, Overwolf, and the Discord Overlay. I'd well believe your points.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#204

Post by rejectfinite »

marcodiego wrote: post #13

> a ~75% CPU usage reduction was noted when browsing YouTube in Firefox I wonder how many of the people who say "Firefox is significantly slower than chrome" are using windows... On my computer, Firefox IS slower than chrome but (with ad blockers enabled) by an insignificant amount. By still being "the last remaining mostly independent, maintained and reasonably popular browser" I'd prefer it to use over chrome even…

>I wonder how many of the people who say "Firefox is significantly slower than chrome" are using windows...

I have heard the most complaints from Mac and Linux users on HN and Reddit. Especially with Youtube...

Windows + Firefox is just fine in my experience. After the Quantum upgrade/version. Yes Chromium based Edge and Chrome is a bit faster, Opera and Vivaldi feel slower depending on the number of tabs.

Firefox and Edge handles many tabs the best from a performance perspective on Windows in my experience. Vivaldi is very close.

Anything without vertical tabs is impossible to use with many tabs.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#205

Post by hoffs »

nikanj wrote: post #184
mconley wrote: post #4

TL;DR: Windows Defender had a bug that made certain system calls expensive on CPU cycles when Defender's Real-time Protection feature is enabled. After discovery, Mozilla reported this issue to Microsoft. Microsoft is releasing a patch that should result in lower CPU usage when using Firefox on sites like YouTube (a ~75% CPU usage reduction was noted when browsing YouTube in Firefox with the fixed version of Defender…

The biggest surprise for me was Microsoft actually fixing it.

They said that Microsoft was already in progress of changing the offending code before Mozilla report.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#206

Post by rejectfinite »

depereo wrote: post #59
JoeAltmaier wrote: post #14

Earlier quoted context omitted.

Funny how that sort of thing can work out. I was involved in an industrial optimization company years ago. Microsoft came out with power-save features in their new release. The staff at a metal-recycling company we were installing at, started complaining that the furnace would stop optimizing overnight. We investigated. The controller computer would go into power-save mode, which suspended our control app. So the fur…

I found a large company was publishing windows server templates to its private cloud clients with power saving mode enabled. The issue I was originally investigating was SQL timeouts; turned out the virtual servers were putting their virtual nics to sleep.

Certified Green Cloud!

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#207

Post by kleiba »

Arrath wrote: post #29
ivanmontillam wrote: post #25

I've experienced a bug related to the on-disk real-time scanning of Windows Defender, but instead with 100% disk bandwidth usage for unreasonable amounts of time. I purchased a license of a proper antivirus software to avoid that bug and the performance issues gone away. When you install another AV software, Windows Defender steps down and leaves scanning to the 3rd-party security solution. I selected one of the most…

> I've experienced a bug related to the on-disk real-time scanning of Windows Defender, but instead with 100% disk bandwidth usage for unreasonable amounts of time. Sophos does this on my work laptop with depressing regularity. At this point I just go grab coffee when the fans max out, cause I know the disk is similarly pegged and it'll be about as snappy as a bogged down Windows 98 machine until it finishes.

I experience the same issue on my laptop, and I've come to think it might be everytime the memory got swapped out. Sophos seems to interfere when the memory is read back from disk, which is annoying and frustrating.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#208

Post by hamilyon2 »

omnimus wrote: post #114
marcodiego wrote: post #13

> a ~75% CPU usage reduction was noted when browsing YouTube in Firefox I wonder how many of the people who say "Firefox is significantly slower than chrome" are using windows... On my computer, Firefox IS slower than chrome but (with ad blockers enabled) by an insignificant amount. By still being "the last remaining mostly independent, maintained and reasonably popular browser" I'd prefer it to use over chrome even…

I have suspicion that lots of the "chrome is faster" is because devs optimise for chrome. More unique and "new" the API is the bigger the difference. Webgl is probably pretty different between browsers but nobody will bother to even look at webgl project in Firefox. It's pretty remarkable that such complex code can run pretty well in multiple different browsers. Another example Chrome has rel=prerender support and so…

Could it be that people compare chrome without an adblocker with Firefox without an adblocker?

If I were Google, I would spend billions on making chrome showing ads really fast.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#209

Post by tomrod »

jdthedisciple wrote: post #165
tomrod wrote: post #82

Earlier quoted context omitted.

Teeny tiny multiplied by 7 Billion by 365 days per year by 24 hours per day by a fraction of a kW does add up.

*8 Billion sir https://www.worldometers.info/world-population/

Oh no! My mistake.

Re: Firefox engineers discover a Windows Defender bug that causes high CPU usage

#210

Post by fransje26 »

lionkor wrote: post #190
qup wrote: post #100

Earlier quoted context omitted.

Yes, I have an absolutely pristine record and I have never, ever copy-pasted a script from the internet with sudo, or piped curl into bash because I'm lazy and I trust most github READMEs. Never.

I usually double check before running stuff as sudo, and piping into bash i dont really ever need (AUR). My heart goes out to those on distros where thats the way to distribute software.

AUR is perfectly safe. Got it.
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