[LITMUS^RT] Question about using ft -- Sisu

[Jonathan Herman]

Hi Sisu,

You need to give the full path to the device and not just the name.
Example: 'sudo ftcat /dev/litmus/ft_trace0 SCHED RELEASE'. See 'ls
/dev/litmus' for all the tracing devices. There is one sched_trace device
per CPU, and one ft_trace device shared amongst all CPUs.


On Wed, Apr 17, 2013 at 12:24 PM, Sisu Xi <xisisu at gmail.com> wrote:

> Hi, litmus developers:
>
> sorry to bother you again. I recompile the kernel and still get this
> message.
>
> xisisu at litmus1:~/ft_tools$ sudo ftcat ft_trace SCHED_START SCHED_END >
> ../temp.out
>  Error: could not open feathertrace device (ft_trace): No such file or
> directory
> Usage: ftcat [OPTIONS] <ft device> TS1 TS2 ....
>
> Options:
>    -s SIZE   --  stop tracing afer recording SIZE bytes
>
>
> However, I was able to get the log file working
> xisisu at litmus1:~/ft_tools$ sudo cat /dev/litmus/log > ../temp.out
> ^Cxisisu at litmus1:~/ft_tools$ head ../temp.out
> 50368 P0: check_for_preemptions: attempting to link task 1081 to 3
> 50369 P0: P0 is closest available CPU to P0
> 50370 P0: (swapper/0:0) will be preempted by base_task/1081
> 50371 P0: (base_task/1081:4579) scheduled_on = P0
> 50372 P0: (base_task/1081:4579) arming enforcement timer.
> 50373 P0: gsnedf_scheduler_tick: 1081 is preemptable  => FORCE_RESCHED
> 50374 P0: enforcement timer fired.
> 50375 P0: (base_task/1081:4579) blocks:0 out_of_time:1 np:0 sleep:0
> preempt:0 state:0 sig:0
> 50376 P0: (base_task/1081:4579) job_completion().
>
>
>
> This is my config file
>
> xisisu at litmus1:~/litmus-rt$ tail .config
> # Tracing
> #
> CONFIG_FEATHER_TRACE=y
> CONFIG_SCHED_TASK_TRACE=y
> CONFIG_SCHED_TASK_TRACE_SHIFT=9
> CONFIG_SCHED_LITMUS_TRACEPOINT=y
> CONFIG_SCHED_OVERHEAD_TRACE=y
> CONFIG_SCHED_DEBUG_TRACE=y
> CONFIG_SCHED_DEBUG_TRACE_SHIFT=18
> # CONFIG_SCHED_DEBUG_TRACE_CALLER is not set
>
>
> any hint about this?
>
> Thanks very much!
>
> Sisu
>
>
>
>
>
>
>
>
>
>
>
> On Tue, Apr 16, 2013 at 2:58 PM, Sisu Xi <xisisu at gmail.com> wrote:
>
>> I just checked my
>> # CONFIG_SCHED_OVERHEAD_TRACE is not set
>> is not set..
>>
>> I'll recompile the kernel with this enabled.
>>
>> thanks all the same.
>>
>> sisu
>>
>>
>> On Tue, Apr 16, 2013 at 2:22 PM, Sisu Xi <xisisu at gmail.com> wrote:
>>
>>> Hi, all:
>>>
>>> I installed the litmus-rt within a guest VM using Xen hypervisor. I can
>>> run base_task without problem, and also I can check the /dev/litmus/log
>>> files. However, when I try to use the ft_tools, it gives the following
>>> errors. Does anyone know why?
>>>
>>> xisisu at litmus1:~/ft_tools$ sudo ./st_trace global-exp
>>> CPU 0: 1081 > st-global-exp-0.bin [0]
>>> Press Enter to end tracing...
>>>
>>> Ending Trace...
>>> Disabling 10 events.
>>> [  259.507087] Failed trace writes: 0
>>> /dev/litmus/sched_trace0: 10176 bytes read.
>>> xisisu at litmus1:~/ft_tools$ cat /dev/litmus/sched_trace0
>>> cat: /dev/litmus/sched_trace0: Permission denied
>>> xisisu at litmus1:~/ft_tools$ sudo cat /dev/litmus/sched_trace0
>>> [  278.522061] Failed trace writes: 0
>>>
>>> xisisu at litmus1:~/ft_tools$ sudo ./ftcat ft_trace CXS_START CXS_END >
>>> ../temp.out
>>> Error: could not open feathertrace device (ft_trace): No such file or
>>> directory
>>> Usage: ftcat [OPTIONS] <ft device> TS1 TS2 ....
>>>
>>> Options:
>>>    -s SIZE   --  stop tracing afer recording SIZE bytes
>>>
>>>
>>>
>>>
>>>
>>>  I am running it on a intel i7 machine, with hyperthreading disabled.
>>> Kernel is configured following the instruction on your website. Seems
>>> litmus is compatible with the xen guest patch. My host runs a normal linux
>>> kernel, 3.4.35 on CentOS 6.3, and my guest VM is Ubuntu 12.04,
>>> para-virtualized.
>>>
>>> Thanks very much!
>>>
>>> Sisu
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Sisu Xi, PhD Candidate
>>>
>>> http://www.cse.wustl.edu/~xis/
>>> Department of Computer Science and Engineering
>>> Campus Box 1045
>>> Washington University in St. Louis
>>> One Brookings Drive
>>> St. Louis, MO 63130
>>>
>>
>>
>>
>> --
>> Sisu Xi, PhD Candidate
>>
>> http://www.cse.wustl.edu/~xis/
>> Department of Computer Science and Engineering
>> Campus Box 1045
>> Washington University in St. Louis
>> One Brookings Drive
>> St. Louis, MO 63130
>>
>
>
>
> --
> Sisu Xi, PhD Candidate
>
> http://www.cse.wustl.edu/~xis/
> Department of Computer Science and Engineering
> Campus Box 1045
> Washington University in St. Louis
> One Brookings Drive
> St. Louis, MO 63130
>
> _______________________________________________
> litmus-dev mailing list
> litmus-dev at lists.litmus-rt.org
> https://lists.litmus-rt.org/listinfo/litmus-dev
>
>


-- 
Jonathan Herman
Department of Computer Science at UNC Chapel Hill
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