isolcpu line: where to locate it ?

bigalex
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13 Jan 2013 19:01 #28647 by bigalex

Replied by bigalex on topic isolcpu line: where to locate it ?

As ArcEye suggested I fit the isolcpu=1 line at the end of the main kernel line (not the recovery one).
I'm not so familiar with Linux so I think for the best that should be nice to implement this information into the wiki page that I mentioned before.

I want to notice to you that the isolcpu=1 line don't apparently have a sensible influence on my system.

Thank you .

bigalex

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ArcEye
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13 Jan 2013 20:43 #28649 by ArcEye

Replied by ArcEye on topic isolcpu line: where to locate it ?

I want to notice to you that the isolcpu=1 line don't apparently have a sensible influence on my system.

The syntax is isolcpus=1 (ie plural), if you have entered what you show, I am not sure if you will get an error or if it will just be ignored

To see if it is running properly run mpstat -P ALL (you will probably have to install mpstat first)

Gives you a printout like below, which should prove that core 1 has been isolated

Linux 2.6.32-122-rtai (INTEL-QUAD) 	13/01/2013 	_i686_	(2 CPU)

12:36:35     CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest   %idle
12:36:35     all        0.16    0.00      14.27    1.30       0.05    0.02    0.00       0.00   84.20
12:36:35       0        0.65    0.00      58.86    5.38       0.19    0.10    0.00       0.00   34.83
12:36:35       1        0.00    0.00       0.00     0.00        0.00    0.00    0.00      0.00   99.99

I'm not so familiar with Linux so I think for the best that should be nice to implement this information into the wiki page that I mentioned before.

I will have a look at the wiki page next week to see what can be added to make it more specific, probably just an example would do.

regards

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bigalex
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13 Jan 2013 21:21 - 13 Jan 2013 21:22 #28651 by bigalex

Replied by bigalex on topic isolcpu line: where to locate it ?

Hi ArcEye

I will be at office tomorrow and I will check it out .
Maybe I am wrong because of isolcpu instead of isolcpus .
No errors during the boot phase so I supposed I did right .
For the wiki page I'm agreed with you about to make an example on this.

Thank you

bigalex :blink:

Last edit: 13 Jan 2013 21:22 by bigalex.

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BigJohnT
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13 Jan 2013 21:42 - 13 Jan 2013 21:43 #28652 by BigJohnT

Replied by BigJohnT on topic isolcpu line: where to locate it ?

Anyone can edit the Wiki page, see the instructions here .

John

Last edit: 13 Jan 2013 21:43 by BigJohnT.

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ArcEye
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14 Jan 2013 18:07 #28678 by ArcEye

Replied by ArcEye on topic isolcpu line: where to locate it ?

Wiki page updated to include an example

wiki.linuxcnc.org/cgi-bin/wiki.pl?The_Is..._Parameter_And_GRUB2

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bigalex
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14 Jan 2013 18:29 - 14 Jan 2013 18:42 #28679 by bigalex

Replied by bigalex on topic isolcpu line: where to locate it ?

Hi ArcEye.

Thank you so much for that and for all the informations you gave me.
I tried your tips (mpstat) and the isolcpus=1 considering using only CPU0 .
The latency test is not too bad (about 35000ns for the base thread and about 70000ns for the servo thread).
The mobo has an embedded ATI low end gpu installed.
I'm using this computer for test in the office (stepper configuration) so I don't need extra performance.
I followed also the user info into the wiki for the BIOS setup.
In any case now is better than before.

regards

bigalex :blink:

Last edit: 14 Jan 2013 18:42 by bigalex.

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