c - Jiffies - how to calculate seconds elapsed? -


i have piece of code, want calculate time in seconds.. though getting time in jiffies, how can convert in seconds?

here kernel code:

#include <linux/module.h> #include <linux/kernel.h> #include <linux/jiffies.h> #include <linux/timer.h> unsigned long js, je, tet; int netblock_init_module(void){     js = jiffies;     printk("\n[jiffies start time : %lu]\nmodule started.\n", js);     return 0; }  void netblock_cleanup_module(void) {     je = jiffies;     printk("\n[jiffies end time : %lu]\nmodule removed.\n", je);     tet = je - js;     printk("\nend time [%lu] - start time [%lu]: \ntotlal elapsed time [%lu]\n",js,je, tet);  }  module_init(netblock_init_module); module_exit(netblock_cleanup_module);  module_license("gpl"); module_description("jiffies example"); module_author("raheel");

output getting this:

$insmod jiffexample.ko

[jiffies start time : 13363583]

module started

$rmmod jiffexample.ko

[jiffies end time : 13361588]

module removed.

end time 13361588 - start time 1336358

total elapsed time [1605]

now want converted time in seconds.. how possible convert elapsed time 1605 in seconds? or alternatively can please tell me how many jiffies in second?

from http://www.kernel.org/doc/man-pages/online/pages/man7/time.7.html:

the size of jiffy determined value of kernel constant hz.

the value of hz varies across kernel versions , hardware platforms. on i386 situation follows: on kernels , including 2.4.x, hz 100, giving jiffy value of 0.01 seconds; starting 2.6.0, hz raised 1000, giving jiffy of 0.001 seconds. since kernel 2.6.13, hz value kernel configuration parameter , can 100, 250 (the default) or 1000, yielding jiffies value of, respectively, 0.01, 0.004, or 0.001 seconds. since kernel 2.6.20, further frequency available: 300, number divides evenly common video frame rates (pal, 25 hz; ntsc, 30 hz).

just divide hz.


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