Messages in this thread | | | Date | Sat, 27 Mar 2004 23:11:35 +0200 | From | Micha Feigin <> | Subject | Re: finding out the value of HZ from userspace |
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On Tue, Mar 23, 2004 at 10:04:22AM +1100, Peter Williams wrote: > 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". >
Unless the kernel is converted to make that conversion possible then it is useless at the moment since userspace gets USER_HZ and the kernel proc interface speaks (KERNEL) HZ so userspace really has no idea how to speak to kernel space with 2.6.
> > > > > >>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 > >> > > > >- > >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/ > > > -- > Dr Peter Williams, Chief Scientist peterw@aurema.com > Aurema Pty Limited Tel:+61 2 9698 2322 > PO Box 305, Strawberry Hills NSW 2012, Australia Fax:+61 2 9699 9174 > 79 Myrtle Street, Chippendale NSW 2008, Australia http://www.aurema.com > > > +++++++++++++++++++++++++++++++++++++++++++ > This Mail Was Scanned By Mail-seCure System > at the Tel-Aviv University CC. > - 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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