Results of latency test, list of computers tested for use with LinuxCNC

Looking good !

HP PRODESK 800 G4 SFF
i5 6500K
32GB RAM (big latency improvement)
2.5" SSD
ATI Radeon HD 6000 (big latency improvement)
6.1.0-13-rt-amd64
LINUXCNC 2.9.1
GRUB_CMDLINE_LINUX_DEFAULT="quiet isolcpus=2,3 intel_idle.max_cstate=0 processor.max_cstate=0 idle=poll"

I have several industrial boards and thin clients and did a quick test on the new 2.9.1 from the download section site. All systems had 4GB of memory each, all power saving features were turned off in the bios.  


2 different boards on J1900:


On one of the systems on the J1800 I did 2 tests, one default with a live install from a flash drive, the other with the system installed and kernel parameters isolcpus=1
 
 
Not very good values, but I think for mesa all these boards will be enough, but for LPT.....

Try without the base thread/period
latency-histogram --nobase --sbinsize 1000 --show

Tried it without the base period, board with J1800: 

 

In any case on the same hardware latency is many times more than on 2.8.4.

Also tried it on an old desktop, E8200, 2GB of memory (one slot on the board doesn't work for some reason), video Radeon HD5450 512Mb:

 

And without GPU:

 

And now I have a dilemma: to use these mini-itx boards with large latency or to put mesa everywhere (but it happens better to use LPT for simple machines). Or look for desktop hardware, but it is not always convenient to place it.

Mesa is great, lots of io, very well supported and reliable.
Pete’s support is out of this world, even to the extent of answering questions regarding running Mesa firmware on Spartan 6 development boards.
Plus it takes the frustration out of latency issues.
Regarding desktops, I have a Lenovo M72e, mini tower, that I found on the street curb, $20 for an quad core I5 and it has awesome latency. Word of warning tho, whilst it does have an on board Parallel port header it does require a genuine Lenovo parallel port cable to work. Tried a standard one and no luck. Haven’t done any reverse engineering of it.