Thread (7 messages) 7 messages, 4 authors, 2011-09-20

profiling functions called in interrupt context

From: anish singh <hidden>
Date: 2011-09-20 11:10:37

On Tue, Sep 20, 2011 at 4:11 PM, Nuno Martins
[off-list ref] wrote:

On Tue, Sep 20, 2011 at 5:59 AM, Amit Nagal [off-list ref] wrote:
quoted
On Tue, Sep 20, 2011 at 10:25 AM, rohan puri [off-list ref]
wrote:
quoted

On Tue, Sep 20, 2011 at 10:13 AM, Amit Nagal [off-list ref]
wrote:
quoted
On Tue, Sep 20, 2011 at 10:05 AM, rohan puri [off-list ref]
wrote:
quoted

On Tue, Sep 20, 2011 at 9:44 AM, Amit Nagal [off-list ref]
wrote:
quoted
Hi ,

i want to measure time spend in a callback function called from
interrupt context .
since the time spend will be in us / ns , what kernel apis can i use
to measure it ?

also since i want to use it in interrupt context ?, kernel time
measurement apis should not sleep .
i am using embedded arm target , and tools like OProfile ?are not
available .

can i be guided which ?kernel time measurement apis shall i use to
measure time in a interrupt callback ?

Regards
Amit Nagal
For this you can make use of ftrace.

Refer link
http://www.mjmwired.net/kernel/Documentation/trace/ftrace.txt

Regards,
Rohan
Tools like ftrace are not available to me in my embedded arm target .
So i want to use kernel apis to deal with time measurement in
interrupt context .

Regards
Amit Nagal
Hi Amit,

I think ftrace can be enabled and used on arm arch.
Please Refer http://www.omappedia.org/wiki/Installing_and_Using_Ftrace

Regards,
Rohan
Ok , ?thanks for the link . i will try the same .
Couldn't use ktimer, it says that is a high resolution timer inside the
kernel, you could combine ktimer with kretprobe (you assing a function prior
to the calling of your function and another when finished ). It is a
instrumentation method inside the kernel.
kernel/Documentation/kprobes.txt
quoted
Regards
Amit Nagal

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Nuno Martins


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