Personal computing discussed

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by chuckula
Mon Jan 15, 2018 5:09 pm
Forum: Linux, Unix, and Assorted Madness
Topic: Bit by Meltdown patch? - VirtualBox hard crashes computer
Replies: 11
Views: 862

Re: Bit by Meltdown patch? - VirtualBox hard crashes computer

OK, I'm on Arch Linux but I just upgraded to 4.9.76 on the host machine and and Virtualbox 5.2.4 booted up my Windows 10 guest VM fine. I have confirmed that KPTI is turned on so I'm Meltdown-protected, although I have not loaded the newest microcode for Spectre just yet due to complaints about it c...
by chuckula
Fri Jan 12, 2018 3:46 pm
Forum: The Back Porch
Topic: TR has fallen victim to Intel's CPU Bug!
Replies: 3
Views: 430

TR has fallen victim to Intel's CPU Bug!

Oh sure, some people thought Intel's side-channel weaknesses were no big deal.

But who knew they could lead to a vicious and unprovoked side-panel attack!

EXHIBIT A!

Image
by chuckula
Thu Jan 11, 2018 9:51 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

I just read the Ars article explaining just why there is a performance impact. It stems from the TLB design. For you smarter gerbils, it's TLB especially hard to design (relative to the complexity of designing processors)? AMD had a bug related to the same thing in the Phenom processors. https://ar...
by chuckula
Thu Jan 11, 2018 4:09 pm
Forum: Processors
Topic: Ryzen's Standings Jan 2018
Replies: 18
Views: 612

Re: Ryzen's Standings Jan 2018

There's only one thing wrong with RyZen: AMD will be launching RyZen+ in March and that is the only event known to modern science that could make RyZen less perfect!

Darn you AMD for innovating at such breakneck speeds!
by chuckula
Thu Jan 11, 2018 1:40 pm
Forum: Mobile Tech
Topic: Drone Talk!
Replies: 26
Views: 2190

Re: Drone Talk!

With CES being in full swing there are plenty of new drones. This one looks interesting not for having high-end technology but for being a $99 drone that provides some degree of user programability. Here's an overview of several new drones at the show including the Tello and higher-end models as well.
by chuckula
Thu Jan 11, 2018 12:58 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

Intel published client impact assessment benchmarks, impact is +6 to -21% AFAICT. Obviously, these are close to besst-case as they are all with CPU well above mid-range let alone low-end, and all Skylake or newer. Good news! Ice Lake can be up to 20% faster than Coffee Lake*! * In benchmarks where ...
by chuckula
Wed Jan 10, 2018 10:36 am
Forum: Linux, Unix, and Assorted Madness
Topic: Bit by Meltdown patch? - VirtualBox hard crashes computer
Replies: 11
Views: 862

Re: Bit by Meltdown patch? - VirtualBox hard crashes computer

Thanks for scaring me! I've updated for Meltdown except for the system that uses Virtualbox to run Windows over Linux.

I would definitely make sure that the kernel modules for Virtualbox have been updated properly as a first step.
by chuckula
Tue Jan 09, 2018 3:50 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

PC Perspective ran a few storage tests (including Optane): https://www.pcper.com/news/Storage/Meltdowns-Impact-Storage-Performance-Really-Issue Short version: There's an impact but it's not catastrophically bad and ironically the 900P SSD actually saw a small reduction in latency that I'm not sayin...
by chuckula
Tue Jan 09, 2018 2:51 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

PC Perspective ran a few storage tests (including Optane): https://www.pcper.com/news/Storage/Meltdowns-Impact-Storage-Performance-Really-Issue Short version: There's an impact but it's not catastrophically bad and ironically the 900P SSD actually saw a small reduction in latency that I'm not saying...
by chuckula
Mon Jan 08, 2018 10:34 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

I think some of the FUD being spread around doesn't survive the light of actual testing, and that includes synthetic benchmarks where the KPTI performance hit is supposed to be "catastrophic". For example: https://www.phoronix.com/scan.php?page=article&item=linux-retpoline-benchmarks&a...
by chuckula
Fri Jan 05, 2018 4:56 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

I would put it this way: What tasks was the machine performing prior to Meltdown and can it perform them post Meltdown? To be fair, I'm mostly asking "for Science!" This machine represents the worst possible case. For me this box is a guinea pig and it will continue to perform that unplea...
by chuckula
Fri Jan 05, 2018 4:39 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

The Meltdown fix does activate, but the CPU lacks PCID and INVPCID instructions. Given that this poor T7500 can't even handle YouTube 1080p decoding, I'm not sure the performance hit the Meltdown patch gives is worth the bit of defense in depth provided. On a machine this old, what useful objective...
by chuckula
Fri Jan 05, 2018 11:49 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

If I'm understanding things properly, the mitigation for Meltdown is going to have more of a performance impact if your processor doesn't support process context identifiers, which means Haswell and newer, but Wikipedia says it was introduced with Westmere. Maybe just for certain SKUs before Haswel...
by chuckula
Fri Jan 05, 2018 10:36 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

I JUST UPGRADED AND IT'S SO SLOW THAT THE KEYBOARD SCANNER CAN ONLY TAKE UPPER CASE LETTERS. Ok not really. Kernel 4.14.11 with KPTI enabled seems to be OK so far. I knew you were kidding because capital letters are bigger, and would therefore be slower... Your technical expertise is obviously much...
by chuckula
Fri Jan 05, 2018 9:44 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

Brief write-up of the major players responses by Ars' Peter Bright: https://arstechnica.com/gadgets/2018/01/meltdown-and-spectre-heres-what-intel-apple-microsoft-others-are-doing-about-it/ The ARS article is pretty comprehensive and not particularly mouth-breathing crazy, which is somewhat refreshi...
by chuckula
Thu Jan 04, 2018 8:09 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

I JUST UPGRADED AND IT'S SO SLOW THAT THE KEYBOARD SCANNER CAN ONLY TAKE UPPER CASE LETTERS.

Ok not really. Kernel 4.14.11 with KPTI enabled seems to be OK so far.
by chuckula
Thu Jan 04, 2018 4:09 pm
Forum: Graphics
Topic: Nvidia forbids GeForce use in Data Centers...
Replies: 21
Views: 1001

Re: Nvidia forbids GeForce use in Data Centers...

This is a semi-related thread about the use of consumer GeForce cards in server cases. It looks like Nvidia is moving more strongly to prevent this from happening beyond the phyiscal setup of its consumer cards.
by chuckula
Thu Jan 04, 2018 11:49 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

just brew it! wrote:
Man, this pair of exploits has turned into a major dumpster fire...


Some men just want to watch the CPUs burn leak information.
by chuckula
Thu Jan 04, 2018 11:05 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

Another idea that would hurt performance but could help mitigate these attacks: Cache flushes that clear out data from other userspace (or kernel space) code so that the only evictions from cache are from your own process context that you presumably can already read anyway. That way any set of cach...
by chuckula
Thu Jan 04, 2018 10:56 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

If the side-channel attack is based at least in part on looking at timing differences for different sets of operations then two major ways to blunt the attack are to either force different operations to take the same amount of time Not feasible in the case of Spectre. The timing difference is based...
by chuckula
Thu Jan 04, 2018 10:25 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

AMD claims the performance hit from KPTI is basically non existent and I feel like it's just a matter of time before someone can make Zen cores do things they supposedly shouldn't allow. AMD argues that KPTI isn't that bad for performance and not Intel? I'd be curious to see that statement (not say...
by chuckula
Wed Jan 03, 2018 9:50 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

It gets better! https://access.redhat.com/security/vulnerabilities/speculativeexecution Additional exploits for other architectures are also known to exist. These include IBM System Z, POWER8 (Big Endian and Little Endian), and POWER9 (Little Endian). So those of you with POWER chips... yes you get ...
by chuckula
Wed Jan 03, 2018 2:11 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

For that matter it's sort of irrelevant if current AMD processors are immune to a particular side channel flaw. I feel this is part of what Glorious is trying to convey to fyo. We've been living for years with a growing category of hardware flaws that bypass KASLR. The KAISER paper already had thre...
by chuckula
Wed Jan 03, 2018 1:44 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

Sorry if I sound stupid but does this affect AMD Zen CPUs? I have heard conflicting reports. Thanks. It doesn't affect Zen. No one has said whether it affects 'dozer, but then again it's possible no one cares about the Construction Cores. I know I don't. I still run an FX-8350, but it sounds like f...
by chuckula
Wed Jan 03, 2018 1:01 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

Sorry if I sound stupid but does this affect AMD Zen CPUs? I have heard conflicting reports. Thanks. According to AMD the same bug that affects Intel chips does not affect Zen because Zen does not perform the same type of privilege-elevated speculative instructions. So this particular bug does not ...
by chuckula
Wed Jan 03, 2018 11:12 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

Krogoth wrote:
It is quite possible that is a flaw from the x86 ISA itself.


Well, if you had read the technical discussion you would know that's completely wrong.
And it would be rather strange for ARM64 to have similar patches posted in November. Which I linked above.
by chuckula
Wed Jan 03, 2018 10:41 am
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

There's a bunch of confusion about what PTI is about. It is a fix for the speculative instruction with ring-level escalation bug that is being talked about here, but it is not only a bug fix for that particular bug. It does provide additional security even beyond this bug at the potential cost of pe...
by chuckula
Tue Jan 02, 2018 10:36 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

For some context about OMG IT'S THE END OF THE WORLD... some synthetic Linux benchmarks showed some hits although the real-world tests like a kernel compile run and x264/FFMPEG encoding were basically unchanged: https://www.phoronix.com/scan.php?page=article&item=linux-415-x86pti&num=1 As f...
by chuckula
Tue Jan 02, 2018 10:13 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

For some context about OMG IT'S THE END OF THE WORLD... some synthetic Linux benchmarks showed some hits although the real-world tests like a kernel compile run and x264/FFMPEG encoding were basically unchanged: https://www.phoronix.com/scan.php?page=article&item=linux-415-x86pti&num=1 As fo...
by chuckula
Tue Jan 02, 2018 2:24 pm
Forum: Processors
Topic: Intel Processor bug incoming?
Replies: 196
Views: 6573

Re: Intel Processor bug incoming?

The apocalypse is CONFIRMED.
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