rtirq or threadirqs or both?
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- funkmuscle
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rtirq or threadirqs or both?
Hey, something just came to my attention after Rui's release of rtirq.
He said used as an alternative to threadirqs.
I remember years ago setting up my system, an article said that I should use both.
So is this true or should I use one or the other or is both ok? I have both running and have had no issues.
If one or the other, which way do you all recommend?
He said used as an alternative to threadirqs.
I remember years ago setting up my system, an article said that I should use both.
So is this true or should I use one or the other or is both ok? I have both running and have had no issues.
If one or the other, which way do you all recommend?
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Re: rtirq or threadirqs or both?
There was a thread recently where @autostatic was clarifying this.
I think rtirq uses the threaded irqs that threadirqs provides. It seems that you don't need the threadirqs kernel parameter when using a realtime kernel, because threadirqs is already part of the realtime kernel. It was less clear whether you need it for the low-latency kernel. I don't think it would hurt, though.
I think rtirq uses the threaded irqs that threadirqs provides. It seems that you don't need the threadirqs kernel parameter when using a realtime kernel, because threadirqs is already part of the realtime kernel. It was less clear whether you need it for the low-latency kernel. I don't think it would hurt, though.
- sunrat
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Re: rtirq or threadirqs or both?
That was this thread in which I plead guilty to leading the topic astray:
viewtopic.php?f=27&t=22864
The conclusion was that threadirqs is not needed for an RT kernel, but needs to be added as a kernel parameter for the Liquorix low-latency kernel I use. Didn't try any other low-latency kernels but autostatic explained in that thread how to determine if threadirqs is active. I did some basic performance testing noted in that thread and threadirqs showed an improvement.
I don't think rtirq script works for non-RT kernels. Edit - it can, see autostatic's disambiguation below.
Last edited by sunrat on Tue Mar 23, 2021 9:11 pm, edited 1 time in total.
- funkmuscle
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Re: rtirq or threadirqs or both?
Thank you very much guys. My question is though that I have the vanilla kernel and a real-time one so when I put that in grub for some reason it attaches it to all the kernels in there.
- sunrat
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Re: rtirq or threadirqs or both?
I would guess the RT kernel would ignore it and the vanilla one would implement it in that case.funkmuscle wrote: ↑Tue Mar 23, 2021 12:52 am Thank you very much guys. My question is though that I have the vanilla kernel and a real-time one so when I put that in grub for some reason it attaches it to all the kernels in there.
- funkmuscle
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Re: rtirq or threadirqs or both?
I hope I gave you a thumbs up and not a thumbs down. Thanks for the answers from everyone.sunrat wrote: ↑Tue Mar 23, 2021 2:14 amI would guess the RT kernel would ignore it and the vanilla one would implement it in that case.funkmuscle wrote: ↑Tue Mar 23, 2021 12:52 am Thank you very much guys. My question is though that I have the vanilla kernel and a real-time one so when I put that in grub for some reason it attaches it to all the kernels in there.
- sunrat
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Re: rtirq or threadirqs or both?
It seems the thumbs down symbol only appears if you have already given a thumbs up, so you can remove thanks if you change your mind. ${deity} help us if LM becomes farcebook.funkmuscle wrote: ↑Tue Mar 23, 2021 2:48 pm I hope I gave you a thumbs up and not a thumbs down. Thanks for the answers from everyone.
And pardon me for not thanking your thanks. The recursive recursiveness would do my head in.
- autostatic
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Re: rtirq or threadirqs or both?
Yes, that's what rtirq is using, you can't put rtirq to full use if you don't have threaded IRQ's as provided by default by a realtime kernel or by a generic kernel with the threadirqs kernel option. Haven't really looked yet at the status of lowlatency kernels when it comes to the use of threadirqs, did a fast check and saw no difference with regard to threaded IRQ's between a realtime kernel and a lowlatency kernel (5.8.0) without the threadirqs option. But I need to double check. And like you said, always adding threadirqs as a kernel option doesn't hurt and that way you're sure you're using threaded IRQ's.
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Re: rtirq or threadirqs or both?
Aaah OK. I thought I had tried it but must have been before I added threadirqs to kernel parameters.autostatic wrote: ↑Tue Mar 23, 2021 8:42 pmIt does but only if you use the threadirqs kernel option.