> Are you playing with the T_LOCK bit? Yes. We do T_LOCK to lock the scheduler while we are in a critical section. Is that why the scheduler does not kick in immediately after the HW int?
-----Original Message----- From: Philippe Gerum [mailto:r...@xenomai.org] Sent: Tuesday, September 29, 2015 11:51 AM To: PRADHAN, MAKARAND (RC-CA); Xenomai@xenomai.org Subject: Re: [Xenomai] Interrupt latency close to 1ms on powerpc Xenomai 2.6.4 On 09/29/2015 05:35 PM, PRADHAN, MAKARAND (RC-CA) wrote: > Hi Everyone, > > I am noticing a delay of around 1ms from the time I get an interrupt and the > time when the user space irq handler task is invoked by Xenomai. Would highly > appreciate any suggestions that will help me resolve the issue. Details > follow: > > System config: > Xenomai: 2.6.4 > Linux: 3.14 > Processor: MPC8360E (powerpc) > > I have a user space task(Task name: 00000193, pid: 30896(ipipe trace)) doing > an rt_intr_wait on int 42(2a). > > The ipipe trace is attached to the email. Am posting my interpretation of the > trace below. It indicates that after the occurance of the int, the previously > executing task continues execution before the int handling task gets > scheduled: > > Occurance of hw interrupt 42(2a) > :| +*begin 0x00000021 -1178 0.666 __ipipe_grab_irq+0x40 > (__ipipe_ret_from_except+0x0) > :| +*func -1178 0.878 __ipipe_dispatch_irq+0x8 > (__ipipe_grab_irq+0x50) > :| +*func -1177+ 1.787 irq_to_desc+0x8 > (__ipipe_dispatch_irq+0xec) > :| +*func -1175+ 1.712 irq_to_desc+0x8 > (__ipipe_dispatch_irq+0xfc) > :| +*func -1173+ 1.712 qe_ic_get_low_irq+0x8 > (qe_ic_cascade_low_ipic+0x1c) > :| +*begin 0x0000002a -1172 0.500 qe_ic_cascade_low_ipic+0x28 > (__ipipe_dispatch_irq+0x94) > :| +*func -1171 0.696 __ipipe_dispatch_irq+0x8 > (qe_ic_cascade_low_ipic+0x34) > :| +*func -1171 0.727 irq_to_desc+0x8 > (__ipipe_dispatch_irq+0xec) > :| +*func -1170+ 1.242 irq_to_desc+0x8 > (__ipipe_dispatch_irq+0xfc) > :| +*func -1169+ 1.212 __ipipe_ack_level_irq+0x8 > (__ipipe_dispatch_irq+0x94) > :| +*func -1167 0.924 qe_ic_mask_irq+0x8 > (__ipipe_ack_level_irq+0x40) > :| +*func -1167+ 1.500 __ipipe_spin_lock_irqsave+0x8 > (qe_ic_mask_irq+0x3c) > :| #*func -1165+ 1.636 __ipipe_spin_unlock_irqrestore+0x8 > (qe_ic_mask_irq+0x94) > :| +*func -1163 0.909 __ipipe_set_irq_pending+0x8 > (__ipipe_dispatch_irq+0x314) > :| +*end 0x0000002a -1163 0.742 qe_ic_cascade_low_ipic+0x3c > (__ipipe_dispatch_irq+0x94) > :| +*func -1162+ 1.606 __ipipe_do_sync_stage+0x8 > (__ipipe_dispatch_irq+0x2f0) > :| #*func -1160+ 2.333 xnintr_irq_handler+0x8 > (__ipipe_do_sync_stage+0x150) > :| #*func -1158+ 1.318 rt_intr_handler+0x8 [xeno_native] > (xnintr_irq_handler+0x150) > :| #*func -1157+ 2.606 xnsynch_flush+0x8 > (rt_intr_handler+0x48 [xeno_native]) > :| #*func -1154+ 1.530 xnpod_resume_thread+0x8 > (xnsynch_flush+0x170) > :| #*[30896] -<?>- 257 -1153+ 4.606 xnpod_resume_thread+0x134 > (xnsynch_flush+0x170) <- Correct irq handler task identified > for resuming > :| +*end 0x00000021 -1148 0.636 __ipipe_grab_irq+0x58 > (__ipipe_ret_from_except+0x0) > :| +*func -1147+ 1.712 __ipipe_exit_irq+0x8 > (__ipipe_grab_irq+0x60) > > > The previously executing thread continues execution for 1076 us: > : +*func -1145 0.833 rt_task_set_mode+0x8 [xeno_native] > (__rt_task_set_mode+0x40 [xeno_native]) > : +*func -1144 0.666 xnpod_set_thread_mode+0x8 > (rt_task_set_mode+0x90 [xeno_native]) > :| +*begin 0x80000000 -1144+ 1.181 xnpod_set_thread_mode+0x408 > (rt_task_set_mode+0x90 [xeno_native]) Are you playing with the T_LOCK bit? -- Philippe. This message and any attachments are solely for the use of intended recipients. The information contained herein may include trade secrets, protected health or personal information, privileged or otherwise confidential information. Unauthorized review, forwarding, printing, copying, distributing, or using such information is strictly prohibited and may be unlawful. If you are not an intended recipient, you are hereby notified that you received this email in error, and that any review, dissemination, distribution or copying of this email and any attachment is strictly prohibited. If you have received this email in error, please contact the sender and delete the message and any attachment from your system. Thank you for your cooperation _______________________________________________ Xenomai mailing list Xenomai@xenomai.org http://xenomai.org/mailman/listinfo/xenomai
