Can jiffies freeze?
coolsandyforyou at gmail.com
Tue Jan 22 13:36:20 EST 2013
Dear Anish, Mulyadi,
this is how i read jiffies.
unsigned long start_time, end_time;
start_time = jiffies;
end_time = jiffies;
I onserved jiffies getting incremented at different place, though
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.
> 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
>> > 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
>> > 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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> With regards,
> Sandeep Kumar Anantapalli,
Sandeep Kumar Anantapalli,
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