OpenBSD was right to disable hyperthreading [video] • Hacker News Board

Re: OpenBSD was right to disable hyperthreading [video]

#21

Post by [deleted] » Tue, Sep 03, 2019, 1:57 PM UTC

Conan_Kudo wrote: post #7

masklinn wrote: post #5

Earlier quoted context omitted.

The BSD troubles rather than wars: it wasn't a spat between BSD distros, it was BSDi and UC (Berkeley) getting sued by USL. It cast a long shadow over the viability of Berkeley at the height of the UNIX wars, and just as Linux was appearing as a completely independent and unencumbered UNIX supported by the maturation & advocacy of GNU and the FSF.

In retrospect, it's probably a good thing. BSD splinters have largely become incompatible with each other, whereas Linux distro splinters have (largely) remained compatible due to licensing and cultural differences. We probably would have had BSD wars for real not long after, if it had become popular. To some extent, this is by design, as there's no culture or ethos that pushes people back together.

[deleted]

Re: OpenBSD was right to disable hyperthreading [video]

#22

Post by chrisseaton » Tue, Sep 03, 2019, 1:57 PM UTC

geggam wrote: post #17

chrisseaton wrote: post #12

Earlier quoted context omitted.

> Because the people who pay folks to work on systems dont like to pay enough money to get that level of talent. People like Google can't pay enough? Do all the BSD developers work as front-end quants or something? How are they all earning so much that nobody can afford them?

Google doesn't use BSD. (to my knowledge) Yahoo! did but they also had BSD developers on the payroll. Any Silicon Valley company will pay enough but that is why when you leave Silicon Valley or a big tech hub everything is windows. The pay attracts the talent.

You said the reason people don't use BSD was because the people who work on it are were too expensive. I know Google don't use BSD, but your idea that it's because they couldn't afford to pay BSD developers doesn't seem to add up, since Google happily pays Linux kernel developers maybe half a million dollars or more. Are the BSD developers really paid so much that Google can't afford them over the Linux developers? That doesn't seem likely to me. I think the reason they're not using BSD is something other than what you're suggesting.

Re: OpenBSD was right to disable hyperthreading [video]

#23

Post by josteink » Tue, Sep 03, 2019, 1:57 PM UTC

danarmak wrote: post #15

Two of the three (current) top-level replies compare BSDs to Linux in general, but that really has nothing to do with whether you disable HT. Using Linux should not have stopped anyone from listening to Theo and disabling HT months ago. Your security authorities don't have to be your kernel developers.

> Using Linux should not have stopped anyone from listening to Theo and disabling HT months ago.

Iirc OpenBSD actively disabled it for you, making it the default.

Nobody else did that.

Re: OpenBSD was right to disable hyperthreading [video]

#24

Post by throwaway2048 » Tue, Sep 03, 2019, 1:59 PM UTC

dnautics wrote: post #10

Perhaps someone might know better than me: why is hyperthreading necessarily bad? Can't you just keep it on and give your tenants cores with affinity? For example, some tenant wants two cores, you give them two vcores on the same core; some tenant wants four cores, you give them two vcores over two, etc.

Because unless you make hyperthreading a purely opt in thing, there is no way to know as a kernel if two things that are security sensitive relative to each other are being run on the same core as Hyperthreading neighbors.

Two threads in a web browser that are assigned to different websites for instance.

Re: OpenBSD was right to disable hyperthreading [video]

#25

Post by robmusial » Tue, Sep 03, 2019, 1:59 PM UTC

For those that can't watch the video GregKH says that OpenBSD was right to disable hyper-threading earlier than Linux in response to Spectre and Meltdown and now Linux disables it too.

He also caveats it by saying they were right for "a little bit of the wrong reasons" but at least in this clip doesn't expand on what he meant by that or what those wrong reasons were or why they were wrong.

Re: OpenBSD was right to disable hyperthreading [video]

#26

Post by throw0101a » Tue, Sep 03, 2019, 2:00 PM UTC

thefz wrote: post #6

mikece wrote: post #2

Why aren’t the *BSD operating systems more popular in the server and workstation spaces?

IIRC Netflix is using FreeBSD. Outside the server scope, OSX is mainly BSD with a different kernel. FreeNAS is based on FreeBSD too.

NetApp, Dell-EMC Isilon, Juniper, iXsystems, pfSense, etc:

* https://en.wikipedia.org/wiki/List_of_products_based_on_Free...

If you follow the commit logs, you'll regularly see "Sponsored by" messages:

* https://www.freshsource.org/commits.php

Not just for the core OS, but also in ports and also drivers (Intel, Chelsio, Mellonox).

FreeBSD in particular has always been persnickety about acknowledging work done on behalf of others. Something that would have prevented the IBM-SCO lawsuit if Linux had used commit/patch tracking from the beggining.

Re: OpenBSD was right to disable hyperthreading [video]

#27

Post by pas » Tue, Sep 03, 2019, 2:00 PM UTC

mikece wrote: post #2

Why aren’t the *BSD operating systems more popular in the server and workstation spaces?

Because you can get the same technical outcome with using off the shelf Linux and setting it up to be conservative just like OpenBSD. (Or simply run sensitive workloads on separated/isolated machines.) The dreaded TCO is likely lower with Linux, because it's easier to work with, better drivers, better performance, more software available natively, and so on. (The whole Linux ecosystem seems more efficient for business, even if OpenBSD/FreeBSD is simply better in a lot of particular stuff.)

Re: OpenBSD was right to disable hyperthreading [video]

#28

Post by geggam » Tue, Sep 03, 2019, 2:02 PM UTC

chrisseaton wrote: post #22

geggam wrote: post #17

Earlier quoted context omitted.

Google doesn't use BSD. (to my knowledge) Yahoo! did but they also had BSD developers on the payroll. Any Silicon Valley company will pay enough but that is why when you leave Silicon Valley or a big tech hub everything is windows. The pay attracts the talent.

You said the reason people don't use BSD was because the people who work on it are were too expensive. I know Google don't use BSD, but your idea that it's because they couldn't afford to pay BSD developers doesn't seem to add up, since Google happily pays Linux kernel developers maybe half a million dollars or more. Are the BSD developers really paid so much that Google can't afford them over the Linux developers? T…

when I said "Work on the systems" I meant support maintain care and feed.

Linux has become mainstream so there are more people in the talent pool to pay to support it.

Windows ... has more so it is cheaper

BSD simply doesn't have enough people who know the system well enough to support it

Paying 5 developers to build something cool doesn't mean you have the support system to run it.... You actually need people who understand your product to use it as a business system

Re: OpenBSD was right to disable hyperthreading [video]

#29

Post by danarmak » Tue, Sep 03, 2019, 2:02 PM UTC

josteink wrote: post #23

danarmak wrote: post #15

Two of the three (current) top-level replies compare BSDs to Linux in general, but that really has nothing to do with whether you disable HT. Using Linux should not have stopped anyone from listening to Theo and disabling HT months ago. Your security authorities don't have to be your kernel developers.

> Using Linux should not have stopped anyone from listening to Theo and disabling HT months ago. Iirc OpenBSD actively disabled it for you, making it the default. Nobody else did that.

If that's true, it's wonderful and I applaud them for making this decision.

I haven't been following this conversation closely; is there any serious change of Linux (some distributions, or the kernel upstream) disabling HT by default?

Re: OpenBSD was right to disable hyperthreading [video]

#30

Post by tyingq » Tue, Sep 03, 2019, 2:02 PM UTC

dleslie wrote: post #9

History will show that Theo was right in a manner similar to how Stalman was right: technically correct analysis and eerily accurate predictions, but lacking in sufficient charisma to create more than a small following. To some extent, you might say they are like Cassandra; speaking the truth but not believed or listened to.

Tannenbaum perhaps somewhere in the middle. Huge install base, but little noteriety.