News for hackers. Stuff that matters.
Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by Filligree on Saturday January 06, 2018 @10:54AM (#16085748)
More than a doubling of CPU use, but for consistency's sake:

The other percentages we've been offered have been in terms of performance reduction. We were told to expect a range of 5-30%; this is about 60%.

Somewhere a sysadmin's hair has started smoldering.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by forgotpw2018 on Saturday January 06, 2018 @11:11AM (#16085838)
Intel's PR dept is in overdrive, but the truth about this vulnerability is that it's essentially worst-case.

It really only affects workloads where high performance is important. The average user might not see an impact but if you need fast IO God help you. The solution is to 'make less syscalls' but the problem is that syscalls have always been slow and the people making a lot of them are only doing so because they absolutely have to

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by djsumdog on Saturday January 06, 2018 @12:31PM (#16086336)
I wonder if we'll start seeing more userspace storage drivers because of this.

If anything, for big shops like this one, I wouldn't be surprised if we saw a move away from hosted providers (the "cloud" .. god I still hate it when people use that word), and return to co-located setups.

At least for people who need immediately performance needs, AMD might make a lot of short term sales right now.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by walshemj on Saturday January 06, 2018 @12:41PM (#16086409)
will be interesting to see the trend in sales of threadripper an eypc
Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by Waterluvian on Saturday January 06, 2018 @11:35AM (#16085941)
Isn't that like saying that it turns out this car we sold can only do 150, not 200. But it's okay because most of you never drive above 80 anyways.

You're right. Most people who just surf the Netflix and download the YouTubes will not notice. But it's still a form of fraud, even to those who never max out CPU. I think fraud is a strong word knowing that this wasn't intentional. But they sold a lesser product than they advertised and need to make customers whole. Otherwise it pretty much is fraud.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by anonacct37 on Saturday January 06, 2018 @12:07PM (#16086140)
I think people are underestimating how bad webapps are. I do... a lot of computing and by far the most CPU intensive applications on my computer are webviews. Either Gmail in chrome or slack. I'm actually going to be upgrading my laptop soon because slack+3 organizations crushes my laptop.

Do you think browser vendors have been pushing JIT research forward, investing in webasm, and building things like servo because websites are so fast and light on CPU?

[deleted]
Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by mistercow on Saturday January 06, 2018 @12:33PM (#16086353)
Is that remotely feasible? You're basically suggesting that Intel needs to refund or replace every PC and server CPU they've sold in the last five years.

The fdiv recall cost Intel almost half a billion dollars, and that was for a small subset of processors that most people didn't replace. Intel has a lot of assets, but replacing five years worth of CPUs might actually bankrupt them.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by forgotpw2018 on Saturday January 06, 2018 @12:43PM (#16086424)
I deleted that because I thought it was too flamey after reading it again, but yeah refunding everyone is unrealistic.

Maybe just average out the performance impact across large cloud providers and offer that as a percentage? It probably wouldn't be hard for a company like Google to crunch metrics before/after the update and give a number for how much their performance has been affected

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by mistercow on Saturday January 06, 2018 @01:41PM (#16086744)
Yeah, I think it's clear that some amount of risk has to be absorbed by the public. It sucks, but it's in our best interest to keep pushing computing forward. And we should keep in mind that it's also not like these attacks are obvious. They took security researchers four years to find.

I think the important thing here is precedent, rather than making customers whole. The question then is what, if anything, could Intel have done to anticipate and prevent this, and how do we incentivize them to take those measures in the future?

It's also possible that there's nothing to change here. There's always going to be some risk, and trying to force that risk closer and closer to zero will at some point not be worth the tradeoff. As bad as this is, if the caution necessary to prevent it would have resulted in processors being half as fast as they are today anyway, there wouldn't be any point.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by metaobject on Saturday January 06, 2018 @11:03AM (#16085788)
I’d go farther, anybody who is concerned with application performance may soon see/smell their hair smoldering.

We write a lot of code that needs to run as fast as possible (processing, post-processing, generating real-time weather/satellite data) and I’m concerned about time windows and whether we’ll be able to meet requirements.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by nine_k on Saturday January 06, 2018 @11:10AM (#16085830)
I suppose these guys just don't apply the patch. They are not running in a public cloud with potentially hostile neighboring VMs; they run their own trusted code. They might choose to tighten perimeter security instead, in the short term.
Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by bsenftner on Saturday January 06, 2018 @11:06AM (#16085809)
Meltdown is aptly named, as that is what's gonna happen to the global corporate services market, "efficiently" hosted in the cloud and scraping for profitability.
Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by rdtsc on Saturday January 06, 2018 @12:15PM (#16086206)
For pure computational cases Meltdown vulnerability remediation might not impact you as much. Meltdown fixes would affect applications that do a lot of syscalls - lots of socket IO, IPC stuff, small and frequent disk IO ops etc.

You'll probably see a wide variety of benchmark results anything from no impact to things like above. So just make sure you measure carefully with your own workload.

Re:CPU Usage Differences After Applying Meltdown Patch at Ep... by toast0 on Saturday January 06, 2018 @12:06PM (#16086137)
Data processing where number crunching is the key problem may not be affected much. Data processing where fetching and assembling the data from many sources is likely to see larger slowdowns. Pure communications workloads are also likely to see larger slowdowns.