Bridgeport Torq Cut 22 Retrofit

I got the computer together today and loaded Linux Mint 19.1 on to it using this guide from BigJohnT , a big thanks for being so thorough.

Compiled and installed the 4.19.1-rt3 #1 SMP PREEMPT RT and then compiled LinuxCNC 2.8 but still need to make the changes to the network adapter to work with a 7i92.

Everything seems to be working great and I am getting decent latency numbers with only a few tweaks in the BIOS:
Servo 1ms: 52639 ns Max Jitter
Base 25us: 54428 ns Max Jitter

My biggest complaint is that I have a fairly slow start up and shut down (compared to my other machine with a Wheezy.iso). Startup is 1m40s, of which it takes a whole minute just to get to the Mint load screen. Shut down takes 1 minute. I did see some info that suggests I could try an older kernel and get better results. I also found this write up from BigJohnT about installing different kernels. I didn't read into it too much and definitely don't have the ability to understand it completely.

If I were to change kernels would I then need to reinstall Linuxcnc after the fact or may I switch kernels fairly freely once they are installed in the system?

Should I really even waste my time?

Michael wrote: If I were to change kernels would I then need to reinstall Linuxcnc after the fact or may I switch kernels fairly freely once they are installed in the system?

Yes you may. And no need to reinstall Linuxcnc.
The long boot time is a pain after getting used to boot times of 20 to 30 seconds.

tommylight wrote:

Michael wrote: If I were to change kernels would I then need to reinstall Linuxcnc after the fact or may I switch kernels fairly freely once they are installed in the system?

Yes you may. And no need to reinstall Linuxcnc.
The long boot time is a pain after getting used to boot times of 20 to 30 seconds.

I was trying to look through BigJohnT's guide to use bash file to unzip and make the kernel here: gnipsel.com/linuxcnc/uspace/latency.html but I couldn't really follow it on the make xconfig part.

I am just going to go the long way I used to get the install originally.

I was able to try another kernel 4.14.28-rt23 but did not get much change in boot time and got worse on the latency test. The default kernel for Mint 19.1 is 4.15.0-70 and had a boot time of 27 seconds. I would like to replicate that with a realtime kernel. Should I look for something closer to that build version to get similar results? I am just guessing on kernels at this point that will improve boot time.

Also had an error making the kernel:
Makefile:947 "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, or....."

I was able to still make the kernel and it seemed to function fine.

I would like to use the bash file BigJohnT made but I don't understand the core comments:
Next depending on how many cores you have add one to that and run make. For 4 cores run make -j5.

If you get an error about not finding Qt4 you may need to install it with

sudo apt-get install libqt4-dev pkg-config

Build the kernel

make -j5
sudo make modules_install
sudo make install

Thanks for all the advice so far. Seems Mesa is sold out of 7i92M's so y project will be experiencing a bit of a delay.

Michael wrote: Compiled and installed the 4.19.1-rt3 #1 SMP PREEMPT RT and then compiled LinuxCNC 2.8

There is probably no need to compile a preempt-rt kermel, as various flavours are available from debian. (the debs install just fine on Mint)

packages.debian.org/search?keywords=linux-image-rt

andypugh wrote:

Michael wrote: Compiled and installed the 4.19.1-rt3 #1 SMP PREEMPT RT and then compiled LinuxCNC 2.8

There is probably no need to compile a preempt-rt kermel, as various flavours are available from debian. (the debs install just fine on Mint)

packages.debian.org/search?keywords=linux-image-rt

Thats probably great and all but I have no idea how to use it. I was following BigJohnT's advice on this page .

I understand their are directions for downloading from the mirror page but it doesn't hold my hand enough to make any sense to me.

Michael wrote: My biggest complaint is that I have a fairly slow start up and shut down

Are you dual booting? Or have maybe installed on OS over another?

I found that my multi-boot machine was taking a long time to boot as the swap partition kept changing names. I had to edit the fstab swap info to match the actual partition name.

This became evident from watching the text at boot time. You might want to turn that on and see if you can spot the thing that takes a long time. The swap thing took some googling, the boot screen said "waiting for a startup job on ..... 5s of 1:30s" or similar.

I am not dual booting, it is a clean install on all new components. It is getting hung up between the flash screen and loading of mint. Originally it was just a black screen for almost a minute. The last few power cycles since messing with kernels have had a "loading initial ramdisk" message then black and then the normal load process that only has one minor hang up.

Getting back to trying a Debian kernel in mint. Is there any good literature to teach me how to do that. I attempted to download the kernel on the page but it says I am missing dependcies. I would love to learn more a out the system overall but at this point am only good at following directions.

I may also give this a shot since it appears it will be the default linixcnc version. I can upgrade it manually to linixcnc 2.8 I have time to play around with some of this stuff this week.
www.linuxcnc.org/testing-stretch-rtpreempt/

Michael wrote: Getting back to trying a Debian kernel in mint. Is there any good literature to teach me how to do that. I attempted to download the kernel on the page but it says I am missing dependcies.

That slightly surprises me. What process did you use?

I would just download the kernel and header .deb files, then "sudo dpkg --install kernel.deb"
Is that what you did?
What were the dependencies?

I did say I wasn't very smart.

It was a pretty simple fix. Downloaded the file from the mirror and used GDebi Package Installer to open it. It was actually telling me exactly what dependency I was missing, but the file name was similar to what I was trying to install so I didn't realize that. I have since loaded the dependency and the kernel.

Boot time is down to 35 seconds with 4.9.0-11-rt-amd64 from the stretch (old stable). The jitter did tick up a bit 60,000ns. I am going to play around with one more of the kernel options and then give the debian stretch iso a try.

Seems like Mesa is out of 7i92M for a bit. If anyone has one for sale or trade I am looking to get rid of a 6i25 that is unused. If I can't find the m then I may settle for the h version.

Edit: 4.19.0-6-rt-amd64 buster (stable) had better jitter at 45000ns and the same boot time.