On Sunday 23 July 2017 11:48:19 dave wrote: > dave@linuxcnc:~$ uname -a > Linux linuxcnc 3.4-9-rtai-686-pae #1 SMP PREEMPT Debian > 3.4.55-4linuxcnc i686 i686 i386 GNU/Linux > > task: 103857488 cycles, min=0.000049, max=0.474214, avg=0.010993, 86 > latency excursions (> 10x expected cycle time of 0.010000s) > > task: 25439189 cycles, min=0.000049, max=0.205898, avg=0.010989, 17 > latency excursions (> 10x expected cycle time of 0.010000s) > > I've done nothing to tune this cpu and as far as I can tell the motion > is ok. > > Still it leave me uncomfortable. > > What do I need to change to clean this uo? > > > TIA > > Dave > How many cores does that cpu have? And if its an intel, is hyperthreading turned on? Thats a bit hard on the latencytest results. Turn it off in the bios.
If 2 or more cores, it may help to add to the grub line that loads the kernel, isolcpus=lastcore, where lastcore could be 2, 4, or even 8 if you've a really new barn burner machine. With that kernel, your dmesg should contain a line: Brought up 2 CPUs The 2 will vary depending on the cpu in that machine, so in this case the kernel loading line in /boot/grub/grub.cfg might have "isolcpus=1" appended to it, without the dbl-quotes. This isolates that core from the scheduler, linuxcnc sees it and uses that core for the realtime part, having it all to itself. But a monitor such as top or htop, can't tell you how hard that cpu core is running. I have one machine still doing software stepping, and that line in its grub has "isolcpus=1 idle=poll", which seemed to help the latency there. And just for my own enjoyment, I usually remove the splash and quiet options. Splash covers up any boot msgs with an ugly graphic, and quiet turns the boot msgs off, which makes the boot faster when it doesn't have to do all the screen stuffs. That way I can scroll back and check that everything looks ok. Or, if mount decides to fsck the drive, you at least have something on screen to explain the delayed boot. I don't normally care how long it takes to boot, only that it boots normally, doing what it has to do to make it run as usual for that machine. I HTH Dave. 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> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
