Messages in this thread | | | Date | Wed, 18 May 2005 17:38:53 -0700 | From | George Anzinger <> | Subject | Re: 2.6.4 timer and helper functions |
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kernel@wired-net.gr wrote: > Hi all, > i am running a 2.6.4 kernel on my system , and i am playing a little bit > with kernel time issues and helper functions,just to understand how the > things really work. > While doing that on my x86 system and loaded a module from LDD 3rd > edition,jit.c, which uses a dynamic /proc file to return textual > information. > The info that returns is in this format and uses the kernel functions > ,do_gettimeofday,current_kernel_time and jiffies_to_timespec. > The output format is: > 0x0009073c 0x000000010009073c 1116162967.247441 > 1116162967.246530656 591.586065248 > 0x0009073c 0x000000010009073c 1116162967.247463 > 1116162967.246530656 591.586065248 > 0x0009073c 0x000000010009073c 1116162967.247476 > 1116162967.246530656 591.586065248 > 0x0009073c 0x000000010009073c 1116162967.247489 > 1116162967.246530656 591.586065248 > where the first two values are the jiffies and jiffies_64.The next two are > the do_gettimeofday and current_kernel_time and the last value is the > jiffies_to_timespec.This output text is "recorded" after 16 minutes of > uptime.Shouldnt the last value be the same as uptime.I have attached an > output file from the boot time until the time the function resets the > struct and starts count from the beggining.Is this a bug or i am missing > sth here???
You are assuming that jiffies starts at zero at boot time. This is clearly not so even from your print outs. (It starts at a value near overflow of the low order 32-bits to flush out problems with the roll over.) > -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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