Messages in this thread | | | Date | Wed, 8 May 2002 12:26:03 -0400 (EDT) | From | "Calin A. Culianu" <> | Subject | Re: Measure time |
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On Wed, 8 May 2002, Der Herr Hofrat wrote:
> > Hello! > > > > Is there any function for high precision time measuring. > > time() returns only in second. I need nanoseconds. > > > you can directly read the TSC but that will not realy give you nanoseconds > resolution as the actual read access even on a PIII/1GHz is going to take > up to a few 100 nanoseconds, and depending on what you want to time > stamp the overall jitter of that code can easaly be in the > range of a microsecond. > > There are some hard-realtime patches to the Linux kernel that will > allow time precission of aprox. 1us (the TSC has a precission of 32ns) > but I don't think you can get below that without dedicated hardware. > > for RTLinux check at ftp://ftp.rtlinux.org/pub/rtlinux/
I recommend RTAI instead. It's more feature-rich, and works with newer kernels.. the url is http://www.aero.polimi.it/~rtai/, or http://www.rtai.org.
-Calin
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