SO here is something you can try, while also documenting this problem for yourself, and others. Get a Wheezy install on sdcard, then update the kernel to a 4.1.x kernel, and then 4.4.x kernels. See where the difference is, *IF* it's a cause of the kernel, or the rootfs.
My guess is that this may have something to do with the 4.4.x kernel, but it's just a guess. On Thu, Jun 9, 2016 at 6:43 PM, <[email protected]> wrote: > We've been using the Beaglebone Black running Wheezy 7.9 to replace an old > legacy piece of hardware, but need it to be backwards compatible. > We have it working and everything is fine, BUT.... > > We'd really like to move it over to Jessie so we can use the cheaper Green > unit (having trouble with the SPI with Green/Wheezy). > > But here's the problem: Moving over to Jessie (even on the BB-Black) > throws off our signal timing. For example when we get > a certain byte of serial data we're supposed to respond with our own in > ~16ms. Code runs fine in Wheezy, in Jessie it responds in over 30ms. > Deal breaker, won't work with the system. I seeing that Wheezy was calling > 'rt-code' so made sure to update Jessie with the 4.1x-TI-RT kernel. > No help. Has anyone had experience with this? > > I'm setting up a repetitive timer and a signal action that is called when > the timer expires. > > ala (brief code follows so you can see the exact stuff) > > //Timer variables > #include <sys/time.h> > > struct sigaction sa; > struct itimerval timer; > > void InitializeTimers() > { > //Install timer_handler as the signal handler for SIGVTALRM > memset(&sa, 0, sizeof (sa)); > sa.sa_handler = &timer_handler; > sigaction(SIGALRM, &sa, NULL); > > timer.it_value.tv_sec = 0; > timer.it_value.tv_usec = > TLI_MaxInterval+(TLI_MaxInterval/4)*(MyTLI_Addr-1); > > timer.it_interval.tv_sec = 0; > timer.it_interval.tv_usec = TLI_MaxInterval; > > setitimer(ITIMER_REAL, &timer, NULL); > } > > I reset this timer every time I get a byte on the serial port. > > > This is some of the system info Wheezy vs. Regular Jessie > > Jessie Settings (Default) > root@beaglebone:~# cat /boot/config-`uname -r` | grep HZ > CONFIG_NO_HZ_COMMON=y > # CONFIG_HZ_PERIODIC is not set > CONFIG_NO_HZ_IDLE=y > # CONFIG_NO_HZ_FULL is not set > # CONFIG_NO_HZ is not set > CONFIG_RCU_FAST_NO_HZ=y > CONFIG_HZ_FIXED=0 > CONFIG_HZ_100=y > # CONFIG_HZ_200 is not set > # CONFIG_HZ_250 is not set > # CONFIG_HZ_300 is not set > # CONFIG_HZ_500 is not set > # CONFIG_HZ_1000 is not set > CONFIG_HZ=100 > > root@beaglebone:~# cat /boot/config-`uname -r` | grep HIGH_RES_TIMERS > CONFIG_HIGH_RES_TIMERS=y > > root@beaglebone:~# uname -a > Linux beaglebone 4.4.9-ti-r25 #1 SMP Thu May 5 23:08:13 UTC 2016 armv7l > GNU/Linux > > > > > Wheezy > root@beaglebone:~# cat /boot/config-`uname -r` | grep HZ > CONFIG_NO_HZ=y > # CONFIG_RCU_FAST_NO_HZ is not set > CONFIG_OMAP_32K_TIMER_HZ=512 > CONFIG_HZ=512 > > cat /boot/config-`uname -r` | grep HIGH_RES_TIMERS > CONFIG_HIGH_RES_TIMERS=y > > root@beaglebone:~# uname -a > Linux beaglebone 3.8.13-bone79 #1 SMP Tue Oct 13 20:44:55 UTC 2015 armv7l > GNU/Linux > > root@beaglebone:~# cat /boot/config-`uname -r` | grep HIGH_RES_TIMERS > CONFIG_HIGH_RES_TIMERS=y > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/a2bb2e2b-61cb-4b0f-b98b-cf88a0dc5d53%40googlegroups.com > <https://groups.google.com/d/msgid/beagleboard/a2bb2e2b-61cb-4b0f-b98b-cf88a0dc5d53%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORq0%2Be%2BcZM7-HFE_o0xXep7TMAs%3DmU74h2um%2BGkgWjN%3DsA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
