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?

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.

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.

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/

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.