When I run my Virtual Machine with Gentoo as guest, I have found that there is considerable overhead coming from tick_periodic function.( this is the function which runs on every timer interrupt).This function updates a global jiffy using write_seqlocks which leads to the overhead.    Here's a grep of HZ and relevant stuff in my config file.sharan013@sitmac4:~$ cat /boot/config | egrep 'HZ|TIME'# CONFIG_RCU_FAST_NO_HZ is not setCONFIG_NO_HZ=y# CONFIG_HZ_100 is not set# CONFIG_HZ_250 is not set# CONFIG_HZ_300 is not setCONFIG_HZ_1000=yCONFIG_HZ=1000# CONFIG_MACHZ_WDT is not setCONFIG_TIMERFD=yCONFIG_HIGH_RES_TIMERS=yCONFIG_X86_CYCLONE_TIMER=yCONFIG_HPET_TIMER=yClearly it has set the configuration to 1000, but when I do sysconf(_SC_CLK_TCK) I get 100 as my timer frequency.So what is my systems timer frequency?  What I want to do is to bring the frequency down to 100,even lower if possible.Although it might effect the interactivity and precision of poll/select and schedulers time slice, I am ready to sacrifice these things for lesser timer interrupt as it will speed up VM.when I tried to find out what has to be done I read in some place that you can do so by changing in the configuration file, else where I read that adding divider=10 to the boot parameter does the job , else where I read that none of it is needed if you can set the (CONFIG_HIGH_RES_TIMERS) to acheive low-latency timers even without increasing the timer frequency and the same is possible with a tickless system CONFIG_NO_HZ.I am extermely confused about what is the right approach.All I want is to bring down the timer interrupt to as low as possible.Can I know the right way of doing this ?  Thanks,Sharan
Lowering kernel timer interrupt frequency
linux;kernel