What kinds of tasks are slower on a micro-kernel? Are there use-cases where a micro-kernel is just as fast as a monolithic?
HelenOS 0.8
11–20 of 57 posts
Re: HelenOS 0.8
#12What kinds of tasks are slower on a micro-kernel? Are there use-cases where a micro-kernel is just as fast as a monolithic?
> What kinds of tasks are slower on a micro-kernel?
Crossing from usermode to kernel is slower, and generally doing complex things in kernel is much slower. (Where complex means cross-cutting concerns, so multiple different kernel processes need to be involved.)
> Are there use-cases where a micro-kernel is just as fast as a monolithic?
Anything that doesn't really involve the kernel much at all, and things that take a lot of time in kernel but do so in one part of it with no need for input from other parts.
Generally, when you go for a microkernel you need to accept that it will be slower than monolithic. It might still be worth it for the advantages of microkernels, namely being easier to verify, understand and secure.
Re: HelenOS 0.8
#13Is there a 'distrowatch' for OSes other than Linux/BSD-based? I can't keep up with them all anymore.
There are sometimes articles here about "off-the-beaten-track" OS: https://www.osnews.com/
Re: HelenOS 0.8
#14Is there a 'distrowatch' for OSes other than Linux/BSD-based? I can't keep up with them all anymore.
osnews.com was once pretty good, but I haven't read it in a while and they did have some recent problems.
Re: HelenOS 0.8
#15For those who, like me, wondered "what's HelenOS?" and got little idea from release notes: http://www.helenos.org/wiki/About
Tiny nitpick but the screenshot showing an application window rotated ~45 degrees is a little terrifying. Why would that be allowed?
Re: HelenOS 0.8
#16Re: HelenOS 0.8
#17For those who, like me, wondered "what's HelenOS?" and got little idea from release notes: http://www.helenos.org/wiki/About
Tiny nitpick but the screenshot showing an application window rotated ~45 degrees is a little terrifying. Why would that be allowed?
Why shouldn't it be allowed?
Re: HelenOS 0.8
#18What kinds of tasks are slower on a micro-kernel? Are there use-cases where a micro-kernel is just as fast as a monolithic?
The basic issue is that, when you make a syscall in most kernels, it needs to do permission/capability checks.
With a micro kernel, it’s more or less inevitable that you have a lot more traffic in and out of the kernel so the overhead tends to be higher.
If your application doesn’t make a lot of syscalls then you won’t have the issue so much e.g. something very compute heavy.
You mitigate the issues, on the kernel side, by making the checks as fast as possible and removing them if it’s safe. On the userspace side, you try to avoid syscalls in performance critical code. Like you would with a monolithic kernel.
Re: HelenOS 0.8
#19For those who, like me, wondered "what's HelenOS?" and got little idea from release notes: http://www.helenos.org/wiki/About
Tiny nitpick but the screenshot showing an application window rotated ~45 degrees is a little terrifying. Why would that be allowed?
You assume that everyone has their monitors the way you do.
At work, I have two large 16:9 monitors rotated in portrait orientation (tall), so this would be useful to me.
Currently macOS only allows 90-degree rotation increments. This allows you to have your monitor in portrait orientation, or mounted from the ceiling or a shelf, hanging upside down so there's nothing taking up space on the desk in front of you.
I've been in a couple of events in the field where having arbitrary application window rotation would have been nice because there was no place flat to put the monitors.
Re: HelenOS 0.8
#20How is it different from [Minix3][1]? It seems to accomplish the exactly same goal.