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    SubjectRe: finding out the value of HZ from userspace
    Micha Feigin wrote:
    > On Sat, Mar 20, 2004 at 12:28:00PM +0100, Stefan Smietanowski wrote:
    >
    >>>>>there is one. Nothing uses it
    >>>>>(sysconf() provides this info)
    >>>>
    >>>>Seems to me that it would be fairly trivial to modify those programs
    >>>>(that should use this mechanism but don't) to use it? So why should
    >>>>they be allowed to dictate kernel behaviour?
    >>>
    >>>
    >>>quality of implementation; for example shell scripts that want to do
    >>>echo 500 > /proc/sys/foo/bar/something_in_HZ
    >>>...
    >>>or /etc/sysctl.conf or ...
    >>>
    >>
    >>Then write a simple program already. How hard is it to write a program
    >>that does a sysconf() and returns (as ascii of course) just the
    >>value of HZ? Then do some trivial calculation off of that.
    >>
    >>HZ=$(gethz)
    >>
    >>If your 500 was 5 seconds, do
    >>
    >>TIME=$[HZ*5]
    >>echo $TIME > /proc/sys/foo/bar/something_in_HZ
    >>
    >
    >
    > Will this be USER_HZ or kernel HZ?
    > Someone earlier suggested it would be USER_HZ which would make it
    > pointless.

    It has to be whatever enables user space to correctly interpret values
    sent to user space as "ticks". That means USER_HZ and it's not useless
    as it enables USER_HZ to be different and/or change without breaking
    programs that use values expressed in "ticks".

    >
    >
    >>I mean, come on.
    >>
    >>Then you include it in the default distro of choice so that
    >>everybody can use it and there you are.
    >>
    >>If someone doesn't have "gethz" then they can download it.
    >>
    >>// Stefan
    >>
    >
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