Real Time Kernel For RHEL 7.4

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Hello

Is it possible to install the RT kernel for red hat 7.4 workstation ?

What Version is it ?

Is there any benefit to it over say an lts kernel from elrepo ?

Kind Regards

Ryan

RC
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Responses

Jamie Bainbridge's picture Red Hat Guru 7257 points
8 September 2017 1:17 AM

We have the Red Hat Enterprise Linux for Real Time add-on product though I expect it's only for the Server product, not Workstation.

You'd only use the RT kernel if you have some high determinism requirement on a single-purpose system. We see this most commonly in low-latency trading where an application must receive and respond to a message within a certain time like 20ms. On these systems CPU usage can NEVER get to 100%. A desktop workload is the polar opposite of what a realtime kernel should be running. There's more about this in the Real Time product doc:

The ELRepo kernel is a completely different thing, that's the latest upstream kernel compiled with a kernel config file which makes it likely to work with RHEL userspace.

What's your actual need here? Why is the regular RHEL kernel insufficient for your needs?

RC Active Contributor 195 points
8 September 2017 2:31 AM

The latest official kernel does not work with the official nvidia driver, i prefer to keep everything in my system as official as possible, with an elrepo kernel i can install the latest nvidia driver and it works correctly, so i believe the issue is either kernel or xorg related

Boot hangs after "Updating system about runlevel changes" attempting to startx manually fails with no screens found, my xorg.conf is generated by the nvidia installer so it should be correct, i can work around it but im more interested in solving the issue rather than stepping around it.

My system is a lenovo p50 set to discrete only with a quadro m2000m graphics card

Jamie Bainbridge's picture Red Hat Guru 7257 points
8 September 2017 5:14 AM

Looking on nVidia forums, there's a patch you can apply to the DRM layer of the proprietary driver wrapper which people say works: https://devtalk.nvidia.com/default/topic/1021871/304-135-fails-to-build-load-on-rhel-7-4-kernel-3-10-0-693/

Akemi Yagi's picture Guru 2404 points
8 September 2017 5:59 AM

That patch is for the 340- and 304-series of the Nvidia driver. If the OP is using the current 384 series, it should run fine under RHEL 7.4.

By the way, ELRepo has patched the kmod-nvidia-340xx package. Anyone using the 340- series should update to version 340.102-4.el7_4.elrepo or newer.

RC Active Contributor 195 points
11 September 2017 7:08 AM

After adjusting the xorg.conf file i did 3 test reboots and on the 3rd attempt the boot hung at "Starting Virtualisation Daemon" , it seems like the config file is correct but its picking and choosing when it wants to boot if i "startx" manually as either root or my user it works, but for some reason it doesn't start automatically.

I've tried X -configure which fails with a segmentation fault, as i continue to fight the problem it begins to look more and more like an Xorg server problem, ive used the same driver and the same kernel on this laptop in the past and it was solid as a rock, ive tried using nouveau on its own just to see how it would work, no boot issues but X does feeze at random intervals with nouveau anywhere from 5min to 30min.

Jamie Bainbridge's picture Red Hat Guru 7257 points
11 September 2017 7:23 AM

That doesn't sound good. You could try the ELRepo kernel as a troubleshooting measure, that would at least tell you if the latest nouveau has some patch we probably need to pull back into RHEL.

If it's an Xorg bug I'm not sure how best to troubleshoot that, X isn't my speciality area. I don't mean to sell you anything, but that may be the point where a support entitlement becomes useful. The problem may be the nVidia driver so I'd definitely try talking to their support before purchasing ours. We wouldn't want you to spend that money only to be told "go ask nVidia".

RC Active Contributor 195 points
11 September 2017 10:48 PM

I got around it by using the maineline kernel from elrepo, i think the cmos battery is gone in my latop because the uefi bio clock keeps resetting, not sure if that has anything to do with it but you never know. i should have grabbed some specific errors but this was late last night and i didn't have enough coffee !

I'd say it's the default kernel not agreeing with my hardware even though the laptop is certified for red hat, very strange

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