On Monday 29 March 2021 10:46:54 Jon Elson wrote: > On 03/28/2021 09:46 PM, Gene Heskett wrote: > > I, for comparison, I just built the latest git pull on my pi4, > > getting these times, which I don't quite grok: > > real 81m28.218s > > user 133m40.185s > > sys 30m24.466s > > > > How do I get user+sys at nearly 2x the real which is the same as the > > actual wall time? > > Doesn't the Pi4 have multiple CPU cores? With 2 cores, > total times can be 2X wall clock time. > > Jon
The pi4 has 4 cores. /boot/cmdline.txt contains isolcpus=3, but I've since read that isolcpus doesn't work on arms of any flavor. Not an error in dmesg but supposedly ignored. Or is it? Running htop from another login shell here, htop numbers them in base 1 format and core 4 is never used, even when linuxcnc is running, so maybe it does work and the uspace version doesn't use it? I'll take that out of /boot/cmdline.txt just for S&G. And now lcnc is using cpu4 at nominally 23% while sitting idle. And does not appear to be jumping around from the deadline scheduler activity. Interesting... But "latency-test -period" is much worse. peaks at 60 some microseconds very quckly. Put it back in, rebooted and now latency-test -period takes 2 minutes to get past 10 microseconds. Strange but thats a kernel I built too. However, htop is seeing it running? On a buster install on an old i5 too!!! Crazy, so isocpus is indeed working on the arms, at least with my armhf kernel. But that kernel install ain't easy. You can't "sudo make install", you have to make a tarball containing the kernel /boot stuff and its /lib stuffs which is about a 30 meg tarball, ship it to this machine, and unpack it to the u-sd card, overwriting the /boot and /lib contents already there. Theres a lot more to it than that doing it the first time though. Read the README.txt in that directory. Goto the link in my sig, and extend the address bar by adding lathe-stf/ which will then show you another directory named linucnc4pi4b where the whole story resides in that README And I forgot but I'd made another link, to the below address, add buildbot-repo, gets you to the same dir. I'll update the lcnc files there shortly. [ 0.601192] SMP: Total of 4 processors activated (432.00 BogoMIPS) Running linuxcnc at 900 mhz/core, it has plemty of time left. I've been out on the net with firefox while lathe-pawn was running in a loop, no problems with how lcnc was running while I was browsing the news sites. Thanks Jon 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
