HZ defined how many ticks the internal timer interrupt in 1sec, which means the number of jiffies count in 1 sec.
Different architecture/machine may have different HZ value, you can check using this script from the timer interrupt:
#!/bin/sh
while [ 1 ]; do
A=`cat /proc/interrupts | grep timer | cut -d ‘:’ -f 2 |sed -e ’s/[^0-9]//g’`
sleep 1
B=`cat /proc/interrupts | grep timer | cut -d ‘:’ -f 2 |sed -e ’s/[^0-9]//g’`
C=$(($B-$A));
echo “HZ:$C”
done
it is around 250 in my desktop running 2.6, but 100 in my mips 2.4 embedded board.
Sometimes we may need to know the time in seconds from jiffies in kernel.
time(sec) = jiffies/HZ;
The script wouldn’t work for me. So I used awk instead of cut. It might be a little simpler also.
#!/bin/sh
while [ 1 ]; do
A=`cat /proc/interrupts | grep timer | awk ‘{ print $2 }’`
sleep 1
B=`cat /proc/interrupts | grep timer | awk ‘{ print $2 }’`
C=$(($B-$A));
echo “HZ:$C”
done