> Gesendet: Dienstag, 08. Dezember 2015 um 12:05 Uhr > Von: "Gilles Chanteperdrix" <[email protected]> > An: "Jochen Behnke" <[email protected]> > Cc: [email protected] > Betreff: Re: [Xenomai] "RT throttling" issue > On Tue, Dec 08, 2015 at 11:42:32AM +0100, Jochen Behnke wrote: > > "ipipe_root_only" also occasionally has long delay times. > > Is ipipe_root_only run when Linux is executing? > > Is this critical? > > See extract below. > > ================== start: extract from frozen file > > ================================ > > : +func -420045+ 1.443 ipipe_root_only+0x4 > > (copy_to_user+0x31) > > : +func -420044 0.260 __ipipe_syscall_root+0x5 > > (sysenter_past_esp+0x5b) > > : +func -420043 0.200 sys_time+0x5 > > (sysenter_do_call+0x12) > > : +func -420043 0.210 get_seconds+0x3 > > (sys_time+0xf) > > : +func -420043! 3910.393 ipipe_root_only+0x4 > > (sys_time+0x1c) > > :| +func -416132 0.651 __ipipe_handle_irq+0x5 > > (common_interrupt+0x2c) > > Hi, > > What you have here is a system call to the "time" function from a > task scheduled by Linux scheduler. When the system call is finished, > the system returns to user-space. ipipe_root_only happens to be the > last function called before the return to user-space and before the > next interrupt. ipipe_root_only gets then charged for the time spent > in user-space. > > What version of the I-pipe patch are you using on which > architecture? On some architectures we try to create trace points > when entering and leaving the kernel to avoid this issue (with the > added benefit that the user-space value of the PC gets printed, this > may be useful if you have an infinite loop). Xenomai: 2.6.4 githead Architecture: x86 Platform: Atom E640/E660 I-pipe patch: ipipe-core-3.8.13-x86-4.patch
Regards Jochen _______________________________________________ Xenomai mailing list [email protected] http://xenomai.org/mailman/listinfo/xenomai
