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 <coolsandyfor...@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 <hejia...@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... >> > >> > >> > >> > >> > _______________________________________________ >> > Kernelnewbies mailing list >> > Kernelnewbies@kernelnewbies.org >> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> >> >> >> _______________________________________________ >> Kernelnewbies mailing list >> Kernelnewbies@kernelnewbies.org >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> > > > > -- > With regards, > Sandeep Kumar Anantapalli, > -- With regards, Sandeep Kumar Anantapalli,
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