Base Period Maximum Jitter -> max number is 50000?

I run latency test and my Base thread : Max Jitter is 63841
So I'm going to fill in Stepper config wizard >Base Period Maximum Jitter 63841 but after I filled it then it change back to 50000 also up-button can not press.

LinuxCNC not except Max Jitter more than 50000? Can I just fill it 50000? Or anyway I can fill 63841?
Is the Servo thread will my issue? It is much value 274100. Since I'm going to use stepper motor machine.

I know mine is not so good number. But maybe I'd try to find another computer. Now that all I've got. Thinkpad T43

thank

If after 50 000 is is not recommended to use linuxcnc, it really does not matter to input 50 000 or 200 000.

wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test

Hi

The thinkpad T43 is a laptop, so never a good idea because of all the power saving stuff etc.

However this has come up before and I think this computer has a chipset affected by the SMI problem.
www.linuxcnc.org/index.php/french/forum/...-seconds-to-be-exact

You will need to be sure, do a lspci -vv, then compare the chipset to the list I put in the wiki
wiki.linuxcnc.org/cgi-bin/wiki.pl?FixingSMIIssues

Manufacturers use the same name for a model that often has different processors, MBs and chipsets through its life, so the name alone is not certain.

If you want to be certain that it is a spike not generally high latency do the rtai latency test and watch for periodic spikes
www.linuxcnc.org/index.php/english/forum...-the-latency-problem

Then follow the instructions in the first link if confirmed

The possible downside is overheating, you will need to carefully monitor this. Part of what SMI is about is monitoring processor temperature and switching the fan on and off or high or low dependent upon the figure.
On a desktop you can just jury rig the fan to be on all the time and forget it.
Might not be so easy on a laptop

regards

If after 50 000 is is not recommended to use linuxcnc, it really does not matter to input 50 000 or 200 000.

wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test

Yes I've read that. Make sense that after 50000 is not recommended.
Also I can't input it more than 50000. So I guess coz it beyond the recommended range so I can't input it right? not a bug?
And I've read topic about SMI also and manage to decrease it to ~60,000. Before it is ~1xx,xxx that is all I've got from my T43.

I'm thinking about buy new pc for LinuxCNC. Coz u not the 1st to tell me that laptop is not good idea.
Also I've experience few hiccup for my step too. So I guess if I've new PC I can stop suspicious to computer and focus worry to my circuit.
Since -ArcEye , u always recommend D525MW Intel Atom board in many topic that I've read in this forum.

ex. www.linuxcnc.org/index.php/english/forum...dware-to-run-linxcnc
ex. www.linuxcnc.org/index.php/english/forum...erboard?limitstart=0

I'm going to have this one too.
1. why u recommend Atom board? Why not i3/i5 board? Does it will slow down thing on Ubuntu? I eager to know coz I've Netbook with win7 NB510 ram4gb ssd256 it is good system fast, only it have little hours power and can't do many thing same time. It will slow down by it's CPU.
2. D525MW Intel Atom + 4GB + 60/128GB SSD is enough for good latency right?

ps. any recommend brand,model ssd for ubuntu?

why u recommend Atom board?

Simply because everyone who has tested one has got good latency figures, usually <10K
They are quite cheap and easy to put together and work off a simple low wattage 12v supply.

Why not i3/i5 board?

Latency is nothing to do with processing power, it is the delay between input and output, to put it simply.
Also latency is best with only one core in use, so that the data in use by the realtime system is always in cache, on that core, reducing latency.
So no point having a multicore processor, the Atom works best when the second core is disabled by use of the isolcpus kernel param.

Also some of the Sandy Bridge chipsets used by the later Intel processors, have appeared not to work at all with a realtime kernel.

D525MW Intel Atom + 4GB + 60/128GB SSD is enough for good latency right?

Plenty, I only have a 32GB SSD, but you probably cannot get them any more, 64GB seems the entry level now
Just buy a branded one, not some Chinese one no-one has ever heard of.
Andy has a 4 or 8GB DOM on one of his and I run another computer on an 8GB CF card, so size is not important above that.

2GB RAM would also be sufficient if on a budget, 32 bit systems can only really see 3.25GB.
You may find it best to remove memory down to 2GB when installing, because the Ubuntu installer will try to install the pae kernel if it detects 4GB of memory
(unless this has been fixed in later Live CDs)

regards

wow! That very clear! So understandable!
I'll try. And report back again.

One thing is for Ram: since this board have 2-slots for ram (if there is 1-slot.... lucky I won't ask again )
I've knowledge that 2-bank of ram that will consider dual-channel. That is benefit for windows. Better bandwidth or something.

How about Ubuntu? Especially when run real-time thing, LinuxCNC. Also benefit? Or maybe not? (I'm so newbie in Linux)

so I should use:
2gb -> 1gb + 1gb or 2gb -> 2gb (also same in 4gb)
What do u think? 1bank of ram or 2 ?

My latestest computer was:

Gigabyte GA-E350N WIN8 AMD Fusion E-350D (Dual core, micro board - same size as the atom ones)
2Gb single slot (this board uses "normal size" RAM that is also less expensive)

And I got better result in linuxcnc than with a dual core 2700 Atom (max jitter 6500 vs 8500), so I can recommend the E 350.

And it have a Radeon onboard, that is much faster in both Linux and windows. Price is similar also.

And it have a Radeon onboard, that is much faster in both Linux and windows

Wow! I personally like Radeon! better in movie player picture quality! thank!
So now I've 2 option

Anyway I don't mind 2 slot of ram so I'd also ask
What u think?

if 2gb --> 1gb + 1gb (2 slot) or 2gb (1 slot)
realtime system or linuxcnc or ubuntu gain benefit?

Unless you are on a very tight budget, just get 2 x 2GB

If you use 1GB sticks, they will be proportionately more expensive
(if you can get them) and if you upgrade later you will have to throw them
away.

That far outweighs any notional performance issue to my mind.

regards

I try to find some answer in single channel vs dual channel effect in performance special in latency.
I found some maybe it benefit to u too. Good knowledge I hope.
After I read this I may try 1x4gb or maybe I'll test the difference myself again in future.

RAM: Single vs Dual Channel speed benchmarks (1x8GB vs 2x8GB)
www.reddit.com/r/buildapc/comments/1fcs7..._dual_channel_speed/

Memory Bandwidth vs. Latency Timings
www.pcstats.com/articleview.cfm?articleID=873

Single channel VS Dual channel ram test


Thank u guy....