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@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@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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-- With regards, Sandeep Kumar Anantapalli,
-- With regards, Sandeep Kumar Anantapalli,