Re: kvm_read() vs ioctl performance

From: Barney Cordoba <barney_cordoba_at_yahoo.com>
Date: Fri, 21 Mar 2008 15:36:24 -0700 (PDT)
--- Julian Elischer <julian_at_elischer.org> wrote:

> Barney Cordoba wrote:
> > I have an app which reads stats from the kernel
> > periodically, and there can be a lot of
> iterations,
> > sometimes 20,000 or more. I'm thinking of
> converting
> > from an ioctl method to kvm_read(). KVM is
> certainly
> > simpler, but its not clear what overhead is
> involved,
> > since kvm_read() likely has to call the kernel
> also.
> > 
> > Does anyone have a handle on the difference in
> > overhead, assuming that the ioctl call is to a
> module
> > which does nothing more than copy the data and
> return?
> 
> tried a shared memory page?

No, but I built a test and kvm_read is 70 times
faster, in
case anyone is interested.

Barney


      ____________________________________________________________________________________
Never miss a thing.  Make Yahoo your home page. 
http://www.yahoo.com/r/hs
Received on Fri Mar 21 2008 - 21:36:26 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:29 UTC