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Old 04-23-2012, 07:38 AM   #1
cruiser
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Reading the value of Jiffies from User Space


Hi,

I want to read the value of jiffies from user space. I understand that the value of jiffies can be read from the Kernel space. Is there a way to achieve this from the user space? Are there any ioctl calls that I can make use of?

Thanks once again
 
Old 04-24-2012, 04:23 PM   #2
d3adc0de
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Why do you want to jiffy your userspace? What are you counting your CPU frequency?
 
Old 05-03-2012, 01:02 AM   #3
cruiser
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"The global variable jiffies holds the number of ticks that have occurred since the system booted. On boot, the kernel initializes the variable to zero, and it is incremented by one during each timer interrupt."

I need to know the time since the last boot and I need this value with a good degree of resolution such as ms (eg 10ms). I have also searched on the net and now found that we cannot read the values of jiffies from User space. However I just wanted to confirm this. I mean is there any or some possibility by which one can get hold and if possible even change this data from User space.
 
Old 08-13-2012, 12:55 AM   #4
cruiser
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Well after a lot of reading, I understand that we cannot access the jiffies value from user space. But coming back to the requirement, a good workaround as I understand is to shoot a timer as the appointed time (preferbly at startup) and let it run continuously. We can then probe this timer at run time, to find the time since the Embedded System has been up.
 
  


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