
Linux 5.6 is the most exciting kernel in years - alexellisuk
https://www.phoronix.com/scan.php?page=article&item=linux-56-features&num=1
======
nrclark
It's great to see all these new features entering the kernel. Here are a
couple of other things I've seen in recent changelogs:

\- The 5.4 kernel can use CIFS as a root filesystem, meaning CIFS can replace
NFS for diskless boot.

\- The 5.3 and 5.4 kernels both include prep for merging PREEMPT_RT into
mainline. This will be a fantastic addition that benefits embedded Linux nerds
like me.

~~~
lucb1e
For more info on the second point:
[https://en.wikipedia.org/wiki/Linux_kernel#Preemption](https://en.wikipedia.org/wiki/Linux_kernel#Preemption)
seems to have something to do with real-time operating systems, but I didn't
dive into it.

Edit: Thanks for the downvotes without commenting what I should do differently
next time?

~~~
hactually
It aims to turn Linux into a real-time OS. The preempty patchset aims to give
faster response times but the main focus is to remove all unbounded latencies
- for example, situations where the delay can vary depending on other factors.

~~~
jschwartzi
This would kill most use cases for QNX+POSIX.

~~~
zozbot234
You'll still need QNX if you want to run a full GUI Unix-like OS from a
_single_ floppy disk.

~~~
jcelerier
Recent QNX has removed Photon and encourages the use of Qt instead which while
can be made small, certainly does not fit in 1.44mb especially in 64bit

~~~
ahartmetz
Yeah, the usual size for a minimal Qt with either QWidgets or Qt Quick / QML
is about 15 MB.

------
ficklepickle
I'm really excited about the NFS client cache stuff.

It's crazy that the whole system grinds to a near halt if it loses connection
to the NFS server, from an end user perspective.

I look forward to some time in the future when Debian incorporates this
kernel. I prefer to use stock kernels. I used to enjoy messing with my
distros, but these days I prefer stability.

~~~
LeoPanthera
I’m not an NFS expert, and I’ve often wondered about client caching of NFS to
improve performance. Does this exist at all currently?

~~~
lazyier
NFS has had caching modes since the beginning. Or at least as long as I have
been using it. It's behavior can be controlled by using async or sync options.

NFSv4 is actually quite nice. Anything earlier should be avoided.

~~~
LeoPanthera
Could you elaborate on why it’s nice? I only ask because the OpenBSD
maintainer, Theo de Raadt, seems to believe, quite strongly, the opposite:
[http://openbsd-archive.7691.n7.nabble.com/nfsv4-td18690.html](http://openbsd-
archive.7691.n7.nabble.com/nfsv4-td18690.html)

I don’t understand NFS well enough to know what to believe.

~~~
Hello71
I've seen that thread before but just read it through in its entirety. All I
got from it was "OpenBSD people are assholes, and not in the Torvalds
'constructive asshole' way, just in the 'being an asshole for the sake of
being an asshole' way".

~~~
tasogare
There is few strong words here and there, but nothing more injurious than what
you would hear by staying in a school for 5 minutes. Once you understand the
liking of such words by their writers, it's easy to mentally replace them by
more politically correct version if it bother you. Moreover, they just critize
tech, not people and that's an important distinction imo.

~~~
IntelMiner
Sorry. No. There's no "political correctness" at here

Theo's comments in particular seem to start at

"NFSv4 is a gigantic joke on everyone."

This isn't politically incorrect, it's just noise. Nothing is gained from this
comment. Even Linus with his infamous "rants" would have actual commentary
laced in, Theo is just being dismissive

After someone reaffirms that they would like to use it, he replies

"Hahahahaha. That's a good one."

"I guess by "all the other protocols" you must be rejecting all the rest of
your network traffic as "not protocols" or "not services"."

Again. Not helpful, just noise

~~~
spookthesunset
Well, to be fair there was at least one poster who suggested that OP use SFTP
instead of NFS... I mean why bother with a vegetable peeler when you could use
a chisel instead?

So yeah, like you said--absolutely no useful information was conveyed in that
thread. Besides any lurking bystanders learning those "in the group" are
complete assholes.

[http://openbsd-
archive.7691.n7.nabble.com/nfsv4-tp18690p1871...](http://openbsd-
archive.7691.n7.nabble.com/nfsv4-tp18690p18719.html)

------
stefs
i don't really understand this: "The AMD k10temp driver finally starts
reporting voltage/current for Zen CPUs and numerous thermal reporting
improvements. This is a big step forward thanks to the community but
unfortunate these Zen/Zen2 thermal/power reporting bits have taken so long and
there are still some mysteries that remain."

why wouldn't AMD set aside a couple of engineers (or at least one) to make
sure their processors are supported here? it's not like this would be a huge
drain on their manpower resources and the company itself should have an
immense interest in the best possible linux support.

~~~
thescriptkiddie
Zen CPUs are notoriously broken on Linux and AMD doesn't seem to care. If you
ever try to install Linux on a first-get Ryzen box and want an uptime longer
than 3 days, you'll want to keep this handy:

[https://github.com/qrwteyrutiyoup/ryzen-
stabilizator](https://github.com/qrwteyrutiyoup/ryzen-stabilizator)

~~~
all_blue_chucks
You have to disable a key security feature (ASLR) to have a stable AMD-based
linux system??

That should have been treated as an all-hands-on-deck emergency by AMD.

~~~
thescriptkiddie
In my case I only had to use the "Power Supply Idle Control" workaround.
Apparently some BIOSes have a setting for this but mine doesn't.

------
cyphar
For some more information on the various features in this release, check out
the 5.6-rc1 LWN[1] article. As usual, that article only covers the first week
of the merge window (Corbet is probably writing the second part as we speak).

[1]:
[https://lwn.net/SubscriberLink/810780/ae4429af6a4ba40d/](https://lwn.net/SubscriberLink/810780/ae4429af6a4ba40d/)

~~~
mrr54
Why are you posting a SubscriberLink to an LWN article to HN? That's not
really the point of the links. They're for sharing in small groups not for
giving away paid content to thousands of people.

~~~
andrewaylett
LWN are happy to see them posted:
[https://news.ycombinator.com/item?id=1966033](https://news.ycombinator.com/item?id=1966033)

------
topspin
There are a number of new io_uring opcodes appearing with 5.6 as well:
fallocate, openat, close, statx, fadvise, madvise, openat2, non-vectored
read/write and send/recv.

------
3fe9a03ccd14ca5
> _Year 2038 work beginning to wrap-up for 32-bit systems_

I wonder how many of these vulnerable systems will be upgraded to kernel 5.6?

~~~
SlowRobotAhead
... I’m struggling to think there was ever a reason to store epoch seconds as
signed.

Was there a use case for “we need to pretend to have 65 years worth of system
time before 1970?

~~~
dredmorbius
From a favourite Reddit thread:

\- Why in the hell would a date value-- particularly one that's an offset-- be
signed?

\- - How were you planning on indicating dates prior to 1970-01-01?

\- - - What date before 1970? We just all assume those do not exist.

\- - - - "Now you've made me feel old." "How old are you?" "Let me put it this
way: when I was born, time didn't exist."

[https://old.reddit.com/r/programming/comments/2b4kpg/conspir...](https://old.reddit.com/r/programming/comments/2b4kpg/conspiracy_and_an_offbyone_error/cj2p2dk/)

The full context is ... kind of fun:

[https://old.reddit.com/r/programming/comments/2b4kpg/conspir...](https://old.reddit.com/r/programming/comments/2b4kpg/conspiracy_and_an_offbyone_error/cj1z7x1/?context=3)

~~~
unlinked_dll
Well if we bite the bullet and use a 512 bit unsigned int we can represent
time zero as the Big Bang and we should be good until the heat death of the
universe, based on my napkin math. But I'm no physicist or kernel contributor
so unsure of the implications.

~~~
war1025
What happens when we revise the moment of the Big Bang? Maybe need signed 1024
bit just in case.

~~~
unlinked_dll
Might as well just make it signed at that point. We'll never need more than
kilibit to represent time.

------
ddevault
Drooling over that picture of a dozen AMD EPYCs. Those processors are
seriously awesome. The newest sr.ht server, tenshi.sr.ht, was provisioned to
run git.sr.ht and has an EPYC 7402 24-core @ 3.35 GHz at its heart. It can
compile the Linux kernel x86_64 defconfig from scratch on an NVMe in under 30
seconds. Our main build server is also EPYC, a 7281.

~~~
the_duke
I usually don't mind some on-topic advertising, but this is a little too bold
for my taste.

~~~
eeZah7Ux
This is not some large corporate-driven, heavily marketed project. It is
_real_ , community FLOSS.

------
Scramblejams
Any indication whether this make it into Ubuntu 20.04?

~~~
gchamonlive
any reason for choosing ubuntu over arch for personal computers? Or any
rolling release distro for that matter

~~~
SmellyGeekBoy
Ubuntu takes all of about 10 minutes to install a full blown desktop and Just
Works™ based on my recent experience. Not to take anything away from the
amazing tweakability and customizability of Arch, but the target audience is
completely different.

~~~
gchamonlive
I use the anarchy distro to help me through the installation. It doesn't
change the fact you need to understand the underlying installation process,
but reduces the installation time to several minutes. There is also arco linux
for a more user-friendly interface

------
jeena
It's interesting to see how adding of features correlates with the quality of
a software. I haven't had problems with wifi on Linux since 2012 (when I came
back to it from OS X after leaving 2006 with huge problems before
NetworkManager was introduced, etc.). It was until two or three months ago
after a kernel update my laptop started dropping the connection with my 5 Ghz
network, only at home. It seems to be a common problem with the Qualcom chip
driver which worked nice on this laptop for almost two years.

I like progressiveness a lot and also new features, etc. and I found a
workaround (switched off 5Ghz at home), so it's ok and I can always install an
older kernel too which is the freedom of free software, I wasn't able to do
stuff like that on OS X.

~~~
theelous3
Ah! I should try this!

Arch on a dell xps, fine for two years and now have some issue where network
buffer doesn't flush (cursory investigation). Have been fairly sure it's an
issue post update. Thanks for the idea :)

~~~
jeena
Yeah mine is a XPS 13 with Arch on it.

------
filereaper
Looking forward to multipath TCP.

Anyone tried it out yet, how does it look so far?

~~~
londons_explore
Looks good to me, but the Google guys are trying very hard to move the web
over to UDP based HTTP/3 instead of MPTCP.

------
openthc
Wireguard!! Woot!

I'll be putting this kernel on all production systems, without testing, on
Sunday night while everyone is off.

~~~
terinjokes
What product are you launching tomorrow morning?

~~~
ioquatix
It's a new blockchain-based analytics database which uses SOAP as the wire
protocol.

~~~
YarickR2
IPO/ICO. Now.

------
pjmlp
> Intel MPX support is completely removed.

A bit sad about this one, Intel should talk to Oracle, ARM and Cambridge
Computer Laboratory on how to implement this kind of feature properly.

------
Andrex
The Year 2038 stuff is cool. Do we have projections for how much unpatched
stuff might still be around in 2038 to cause issues? The benefit of getting
the fixes merged 18 years ahead of time is so those fixes proliferate, but I
have to imagine there's a nonzero amount that won't/can't upgrade... Curious
if there's any idea of how big an issue this could be, even if we solved
everything today.

------
gjsman-1000
Rc1 was released just 30 minutes ago! I’m compiling away!

------
JohnFen
There's certainly a lot in there!

However, there's not much that is of interest to me. Given that, plus the
mammoth amount of changes in the kernel, I think that I'll be delaying
updating to this kernel for a good, long time. Just in case.

------
purplezooey
crap there's a USB4 already?

------
megous
Already compiling... :)

------
rmrfchik
I've rolled back to 4.19 as 5.x kernels works very bad on my setup. Any IO
makes system unresponsive. Box is i7, integrated video, ram 32Gb, SSD 512Gb
running debian testing. run "apt update" and mouse stops, music skips. 4.19
runs flawless under any reasonable load on this system.

~~~
LinuxBender
What options do you see in /proc/cmdline when you are on 5.x?

~~~
LinuxBender
And could you add the output of 'lspci -vv' perhaps on pastebin

------
todd3834
This sounds like a lot of impressive work. I wonder if there would be any
benefit to the Linux kernel adopting more of agile release cycle. This
waterfall like release surely has to increase the risk surface.

Perhaps the mindset of web software and operating system kernels don’t overlap
enough for this to be reasonable?

~~~
todd3834
Not sure why getting downvoted. Is this an ignorant question? Or maybe just
not fans of the word agile? Oh well. Guess I’ll just have to ask someone who
contributes the the kernel in person the next time I meet one.

~~~
wtallis
It's a pretty ignorant question; it could also be taken as flamebait trying to
start up an agile vs waterfall argument.

New stable kernel branches are released every 2-3 months after weekly release
candidates, with bugfix releases in between new stable branches and a new LTS
branch every year or so. If you want anything "more agile" than that for OS
kernel development, then you're probably prioritizing agile dogma over the
realities of trying to not break the most fundamental component of the
operating system.

~~~
pmlnr
Agile is juatvas much about small features as time. Imo this kernel comes with
too many changes; smaller steps miggt be preferable.

~~~
wtallis
It sounds like you're just not accustomed to paying attention to a project
with such broad scope. Most of these changes have fairly narrow impact on just
a single driver or subsystem. It would be silly to say "we're going to
postpone release of this new GPU driver because we have too many new network
drivers in this release", because there's no reason to expect such a policy to
actually improve the quality of kernel releases, and it would obviously be
detrimental to the pace of feature additions.

Actual far-reaching systemic changes are a pretty small portion of this and
most other stable kernel releases.

