Can jiffies freeze?

[sandeep kumar]

Dear Anish, Mulyadi,

this is how i read jiffies.

unsigned long start_time, end_time;
start_time = jiffies;
free_area(***);
end_time = jiffies;
printk("%ld", end_time-start_time);

I onserved jiffies getting incremented at different place, though

thanks
sandeep



On Tue, Jan 22, 2013 at 10:29 AM, sandeep kumar
<coolsandyforyou at gmail.com>wrote:

> Hi All
> I am seeing this problem at the very early in the start_kernel-->
> mm_init--> free_highpages, at that time nothing is up and kernel is running
> in single thread.
>
> Thanks
> Sandeep
>
>
> On Tue, Jan 22, 2013 at 1:07 AM, hejianet <hejianet at linux.vnet.ibm.com>wrote:
>
>> how about to check the disable/enable timer interrupt?
>> cat /proc/stat before/after 2 seconds?
>> On 2013-01-22 13:51, sandeep kumar wrote:
>> > Hi all
>> > As far as I know jiffie counter is incremented HZ times/second. And it
>> is
>> > used to measure the time lapses in the kernel code.
>> >
>> > I m seeing a case where, actualy time spent in some module using
>> giffies is
>> > zero, but while seeing UART logs i am seein 2 sec time difference. I
>> dont
>> > know how to interpret this. The case which i am seeing, hrtimers are not
>> > enabled yet, so only thing i can rely are on jiffies.
>> >
>> > My question here is,
>> > Is it possible that the measured time lapse shown is "0"(jiffie count is
>> > same before and after), but actually some time is spent?(say some 2 sec)
>> >
>> > In another way..can jiffies may freeze for some time?
>> >
>> > Please clarify...
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>>
>>
>>
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>
>
>
> --
> With regards,
> Sandeep Kumar Anantapalli,
>



-- 
With regards,
Sandeep Kumar Anantapalli,
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