On Thursday 23 August 2018 12:01:41 Chris Friesen wrote: > On 08/23/2018 07:45 AM, Gene Heskett wrote: > > LinuxCNC is also run as a common user, never as root. Thats my > > $0.02 from a users viewpoint. > > Given that these are special-purpose machines, can I ask why you > wouldn't run as root if it gave better performance? > > Chris Its a rather bad habit, and if I get used to doing it on this machine, I might do it on one of the metal carvers, which has a tendency to mess with the user perms. Root or known user is all the same to lcnc AFAIK. I have done it 3 or 4 times, but there is no detectable diff in performance. But sometime in the last few years it has now been trained to refuse to run as root. The kernel argument isolcpus= comes in handy occasionally on really old but still multicore hdwe but has had little or no effect since about kernel 3.4.0 built for SMP and PREEMPT. We don't use more than 2GB of d-ram for the same reason, the patches to give a 4GB capable address are also a performance penalty. Currently running Linux GO704 3.4-9-rtai-686-pae #1 SMP PREEMPT Debian 3.4.55-4linuxcnc i686 GNU/Linux, a 32 bit build because its faster at a context switch than the larger stack image the 64 bit build uses. This machine, my "doitall" machine doesn't drive any of that sort of hardware, and is currently running:3.16.0-0.bpo.4-amd64 #1 SMP Debian 3.16.39-1+deb8u1~bpo70+1 (2017-02-24) x86_64 GNU/Linux which will run the simulator so I can write cgode from a comfy chair. Then export it with sshfs to the machine that will actually make the swarf, aka metallic sawdust. Thanks Chris. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
