Can jiffies freeze?

sandeep kumar coolsandyforyou at
Tue Jan 22 00:51:06 EST 2013

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...

With regards,
Sandeep Kumar Anantapalli,
-------------- next part --------------
An HTML attachment was scrubbed...

More information about the Kernelnewbies mailing list