341–350 of 567 posts
Can anyone with better knowledge ELI5 to me -- to fix this bug, are cloud providers have to patch only hypervisor machines, or guest boxes as well? And if fix is applied to hypervisor, will performance degrade on guest boxes as benchmark suggests? Thanks!
Can someone help me understand why this is such a big deal? This doesn’t seem to be a flaw in the sense of the Pentium FDIV bug where the processor returned incorrect data. It doesn’t even seem to be a bug at all, but a side channel attack that would be almost expected in a processor with speculative execution unless special measures were taken to prevent it. And it doesn’t seem like it can be used for privilege esca…
There is this thing called "return oriented programming". You write your program as a series of addresses that are smashed onto the stack through some other type of vulnerability. When the current function returns, it returns to an address of your choosing. That address points to the tail end of some known existing function, such as in the C library and other libraries. When the tail end of that function returns, it…
This is a clusterf /big deal. Beyond the security implications, it means that all companies paying for computing resources will have to pay roughly 30% more overnight on cloud expenses for the same amount of CPU, assuming that they can just scale up their infrastructure. I know that bugs happen and that there was nothing intentional on this one, but at times like this is hard to held at bay the temptation of claiming…
It's a good thing CPU is fairly compressible. Unless you meter it very carefully, you'll see the performance hit and it'll not impact you that much. Very few of my physical boxes are over 70% CPU utilization on a daily average. It's, however, really bad if you sell CPU cycles for a living. You just lost between 5 and 30% of your capacity. If you have a large building, you just lost part of your parking lot to the Int…
Who really sells CPU cycles? Cloud providers sell instances priced per core. So the real hit is by the customers since they have to shell out for more instances for the same amount of computing power.
The hit I see is by providers of 'serverless' computing, since they charge per request and have their margins reduced.
Earlier quoted context omitted.
> For some reason I can’t reply to ‘chrisper’ HN doesn't let you do this to new comments to avoid back-and-forth commenting that is typical in flamewars.
Coming up on 9 years here and I'm still finding out new things about how this site works. I've been wondering recently why some comments aren't replyable.
You can reply anyway, but you have to click on the timestamp ("X minutes ago") to do it.
This is a clusterf /big deal. Beyond the security implications, it means that all companies paying for computing resources will have to pay roughly 30% more overnight on cloud expenses for the same amount of CPU, assuming that they can just scale up their infrastructure. I know that bugs happen and that there was nothing intentional on this one, but at times like this is hard to held at bay the temptation of claiming…
It's a good thing CPU is fairly compressible. Unless you meter it very carefully, you'll see the performance hit and it'll not impact you that much. Very few of my physical boxes are over 70% CPU utilization on a daily average. It's, however, really bad if you sell CPU cycles for a living. You just lost between 5 and 30% of your capacity. If you have a large building, you just lost part of your parking lot to the Int…
30% is a big hit. I'm wondering if that isn't a bit exaggerated, or perhaps the consequence of a poorly optimized workarounds that will rapidly improve. I recall seeing figures on the order of 3% only a few days ago.
Earlier quoted context omitted.
From what I've read, this slowdown only affects syscalls, which, since they aren't usually a huge percentage of processing in the first place, should not have such an effect. You're more likely looking at a few percent at most, which is not going to be enough to make AMD outperform Intel. Let's stop the fear mongering and wait for actual metrics.
Prelim benchmarks show a significant impact (~20%) on Postgresql benchmarks.
[1] http://lkml.iu.edu/hypermail/linux/kernel/1801.0/01274.html [2] http://lkml.iu.edu/hypermail/linux/kernel/1801.0/01299.html
This piece is (IMNSHO) trash. It's trying to stare into some crystal ball guessing at the cause of market fluctuations; but there's no real evidence they're right. Not to mention it's pretty misleading about technical stuff, saying e.g. "Chip design errors are exceedingly rare. More than 20 years ago, a college professor discovered a problem with how early versions of Intel’s Pentium chip calculated numbers." So, the…
Major chip design errors, of this magnitude, are exceedingly rare. Especially in comparison to the software industry where bugs are released to production a couple orders of magnitude more frequently. How many other Intel hardware bugs can you point to that are comparable to the ones below? "All computers with Intel chips from the past 10 years appear to be affected... The security updates may slow down older machine…
Disabling a whole feature (TSX) across an entire generation of processor and early steppings of the next? That's pretty major, given it's a marketed feature.
Earlier quoted context omitted.
Not by default they don't. That only works if you're willing to dedicate that entire physical drive to a single application anyway.
In the future this possible on Linux with the filesystems that support DAX. Currently this all pretty experimental with lots of work being done in this space in the last two years. But this will require you to have the right kind of flash storage, right kind of fs, right kind mount options, and probably a different code path in userspace for DAX vs traditional storage. So we're a little ways away from this.
That doesn't move anything from kernel land into userspace, certainly not in the app's process in userspace anyway.
Earlier quoted context omitted.
You're putting words in my mouth. I didn't say he didn't know about it. I said we don't know WHEN he first knew about it, which is important in the context of insider trading.
Even if he knew about it, if it was more than 6 months in advance and he follows all the legally-mandated protocols for setting up a regulated stock trade, isn't he safe? The marvel is that somehow the news was kept from hitting the media until he had finished his trade, and then was revealed immediately after the transaction was complete. I wonder how that coincidence happened.