Re: isolcpus question

Gene Heskett
2012-01-31T06:31:27Z

On Monday, January 30, 2012, Mike Galbraith wrote:
>On Mon, 2012-01-30 at 22:13 -0500, Gene Heskett wrote:
>> Which is, is there a isolcpus troubleshooting tool?
>>
>> I have an app that is supposed to use the 2nd cpu on a 2 core atom
>> system all by itself, and its insisting on using cpu0 when the boot
>> command line has "isolcpus=1" appended to it, and apparently I am the
>> only one with the problem, its working for about 200-500 others
>> running the same software.
>
>isolcpus=1 isolates CPU1 so no task will automatically end up using it,
>but it's up to your task (or you) to move to the isolated CPU. Pin your
>task to CPU1 with taskset, and all should work fine.
>
> -Mike

Cross-posted back to the emc-users list, others might find it useful also.

Mike, you're a genius. The man page for taskset is a bit obtuse but the
first stab at a '/usr/bin/lcnc' script:
-------------
#!/bin/bash
taskset 0x00000002 emc -l
exit 0
-------------
Seems to launch this application and I believe its now working better than
ever before. Now I need to do some experimenting to see just how fast I
can make linuxcnc's base_thread run without the rest of the box getting
laggy. The faster I can make that thread run, the faster and smoother my
steppers driving my milling machine will run. I have already cut it down
to 30 u-secs from 65 u-secs and it is still only using about 26% of the
target cpu1. Amazing IMO.

Thank you very much Mike.

Cheers, Gene
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