Le 18/11/2016 à 19:17, Philippe Gerum a écrit :
On 11/15/2016 11:01 AM, Stéphane ancelot wrote:
Hi,
In order to solve my realtime pb, I have a bit some problems to
understand my ipipe trace that has been frozen.
My task should normally spend almost 200us to run and in this case, it
spends more than 500us.
My task starts at -723 and stops at -14.
I made some comments in the trace, but have problem understanding where
is the biggest problem.
[snip]
(__cobalt_mq_timedreceive+0x25c)
:| + begin 0x80000000 -439 0.220 hard_local_irq_disable+0x16
(__xnlock_get_irqsave.constprop.11+0x9)
:| # func -438 0.493 __put_fd+0x0 (rtdm_fd_put+0x22)
:| # func -438 0.206 __ipipe_restore_head+0x0
(__xnlock_put_irqrestore.constprop.10+0x67)
:| + end 0x80000000 -438! 423.494 hard_local_irq_enable+0x17
(__ipipe_restore_head+0x70)
This section denotes a transition to user-space, the application code
resumes from a mq_timedreceive() call, running for 423 us before issuing
another Cobalt syscall:
: + func -14+ 2.201 ipipe_fastcall_hook+0x0
(system_call_after_swapgs+0x6b)
: + func -12 0.543 handle_head_syscall+0x0
(ipipe_fastcall_hook+0x18)
Of course, assuming x86 is your target architecture, this might be a SMI
event happening during this transition too, but I would investigate the
most probable (and fixable) cause first.
I made some more analysis.
I made a ftrace using kernelshark here are 3 interestings screenshots.
on cpu2, task automat , there are 511 us without any visible activity in
it !.
on other processors there is X and network activity.
at following timestamps :
242.575596 task automat is being activated, switching from
threadreception (thread reading rtnet network interface).
242.575601 task automat resumes from nanosleep that was waiting for
network data and continues to run
no more activity up to 242.575914 timestamp on cpu2 , where it detects
global time overlap for task automat, it has spent almost 300us, where
it should last almost 100us....
https://drive.google.com/open?id=0B1JEDrsMi1E1YllGNDBFRVBnYW8
screenshot 1
https://drive.google.com/open?id=0B1JEDrsMi1E1dHFRYURvaGtjTnc
screenshot 2
https://drive.google.com/open?id=0B1JEDrsMi1E1X3hQV1Jsb2hjdjg
screenshot3
https://drive.google.com/open?id=0B1JEDrsMi1E1WWFjdXVUQjA5WU0
corresponding ipipe trace :
https://drive.google.com/open?id=0B1JEDrsMi1E1YllGNDBFRVBnYW8
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