Reducing latency on multicore pc's - Success!

Are there any more easy tricks?

You could try the RTAI kernel and matching LinuxCNC version.
I have a Core i3 machine with a latency < 2000nS. But that isn't an RTAI thing, that machine is just as good with preempt-rt. So it is more often the motherboard than the CPU that determines latency.  

Thanks for the reply. Today I tried with the official intel drivers using MXTweak but it made it worse ~+70k ns.

Turning everything off from bios and seems I end up in around 150uS servo and 90uS base threads (I will need to playaround with the graphics memory etc in bios).

As I see preempt RT probably being supported more and more in the future, I would like to stick with that (please correct me if I am totally off).

I just assume that 150uS latency with Mesa cards is not "that" bad? Should I try with different RT kernel versions?

Different RT kernel versions matter as does the OS.

On “sensitive” h/w I have found, using the same kernel and kernel options, significant latency differences between Debian and Mint.  I don’t know why it happens but time and again I have found a Mint install on the same sensitive kit trounces Debian. Even with the same kernel versions.

To be fair this is on kit that is sensitive and requires the setup to be “just so”.

I would suggest some experimentation beyond the official debian path if you are looking get the best out of kit that is not immediately sub 70us on offical lcnc debian.    For example, i now have an HP thin client machine running a very frugal AMD T56N on Arch Linux RT kernel delivering ~~26 servo jitter.  Debian 10 and 11 measured materially north of 100us (120+ from memory).  Mint19 gave ~35us. 

Please note that the key here is SENSITIVE kit.  I have a dell 3020 machine on debian 10 delivering excellent jitter. Experimentation deliver real wins, just be prepared to invest the time.  

Cheers - J. 

Andy - is that i3 machine a custom build or something stock from big name like HP, Dell etc?  If the later what exact model?

No eBay APP ID and/or Cert ID defined in Kunena configuration

Joco wrote:

Andy - is that i3 machine a custom build or something stock from big name like HP, Dell etc?  If the later what exact model?
 

It's an RM-One 310: 

Mainly bought as an easy machine to move about the place. But with Parallel port and two PCI slots it makes a good test bed machine as it can run any Mesa card. 

Hello..

I followed the first post of this discussion steps and got some improvement in latency value..

But I could not complete the step: - add the upstart script "irq-affinity.conf" to /etc/init (see attachments, it will move the irq-handling to the first core)

can anyone demonstrate/ what are the exact steps/commands..I am not a computer guy.

Thanks,