Earlier quoted context omitted.
the Hurd-verse lives! Richard Stallman is a clean-shaven, foulmouthed autocrat, and Linus is composing folk songs about joining hands with Intel and Nvidia!
Who is dressing up as a monk?
[deleted]
The Jury Is In: Monolithic OS Design Is Flawed [pdf]
41–50 of 199 posts
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#42Earlier quoted context omitted.
Lack of performance on microkernels is a myth nowadays. QNX and many embedded OS, some of which driving high integrity software, are all microkernel based. Including the one most likely handling the real time communication of this mobile radio.
"Fast enough design" does not equal "faster design".
Particularly if you're doing kernel bypass for performance reasons, the smaller cache footprint of a microkernel is an advantage.
When I was in college, the first assignment was to run a provided benchmark program that jumped all over a gradually growing buffer and graphed average latency vs. buffer size and we had to identify the sizes of thle various caches from the generated graphs. I was tripple-booting Linux Windows, and QNX at the time and did the same assignment on each OS (identical hardware). QNX had more sudden transitions between latency levels due to delaying transition later due to smaller cache footprint.
If your userspace NIC driver and TCP/IP stack are implementee as a library and you are running your high performance application on a dual NIC box, your application can be the driver for one of the NICs and the other NIC can handle everything else. It's hard to beat zero copy/zero context switch I/O. Of course, putting the application in the kernel would yet be faster, at least if in both cases the kernek's cache footpint is tiny.
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#43Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#44> We find that almost all exploits are at least mitigated to less than critical severity, and 40% completely eliminated
This probably sounds trollish, but security isn't that important. An OS architecture has to take into account other things too.
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#45I wonder if there exists a parallel dimension where linux is microkernel design and folks are pushing for monolothic citing the driver friendliness and performance
If parallel dimensions exist, then it's most certainly one of the closest dimensions to ours. If I'm sure of one thing, it's that as soon as we decided to build everything as Microkernels, we'd have the same squeaky wheels touting the massive benefits of Monotlithic OS design. We're hilariously cyclical in our preferences. "Think of all the runtime efficiencies of the shared memory, and how much easier it would be to…
The dirty secret is that we take a microkernel, rename the syscalls as "upcalls", throw in some hardware emulation code as a less efficient and uglier API for software that can't be bothered to be ported, and call it a hypervisor.
Also, your phone's baseband processor almost certainly runs a microkernel, and likely so does your car.
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#46Earlier quoted context omitted.
Lack of performance on microkernels is a myth nowadays. QNX and many embedded OS, some of which driving high integrity software, are all microkernel based. Including the one most likely handling the real time communication of this mobile radio.
It's not a myth. Real time doesn't mean fast, it just means deterministic. And I'll throw out there that many times the the term microkernel in a lot of embedded OSs has been contorted by marketing speak into something unrecognizable. Basically if you have multiple threads in the kernel, structure the kernel code into modules (but perhaps don't even allow dynamic loading of modules), and can communicate through async…
vezzy-fnord had a lot to say on that subject.
* https://blog.darknedgy.net/technology/2016/01/01/0/ (https://news.ycombinator.com/item?id=10824382)
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#47Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#48That chart with the growth of the Linux kernel discredits everything. The Linux kernel continues to grow because they are obsessed with keeping all drivers in mainline instead of having a stable API for them as any sane project would.
RHEL does provide a stable kernel ABI (kABI) that can be and is used by vendors to ship binary drivers. See https://elrepo.org/tiki/FAQ
When I worked for a NIC hardware vendor, we would ship our driver in 4 forms:
1) source tarball
2) upstream kernel
3) RHEL/Centos kABI compliant source and binary rpms
4) Debian pkg using dkms
The upstream kernel driver wasn't good enough for a variety of reasons. For example, on Ubuntu LTS and RHEL, the in-tree driver was often based on a kernel that was several years old and which lacked support for recent hardware or features.
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#49I wonder if there exists a parallel dimension where linux is microkernel design and folks are pushing for monolothic citing the driver friendliness and performance
This would be the world of Windows NT in between version 3.5 and 4.0.
Re: The Jury Is In: Monolithic OS Design Is Flawed [pdf]
#50In a perfect wrold microkernel OSes would be perfect but then it's all pointless.
In real life there are certain parts of the OS that have to work or the whole device stops working. Furthermore: the isolation of dynamic and less tested application code from these parts is generally a good idea, that's why monolithic OSes are so popular; they're simply less demanding.