Re: Timer idea

[George Anzinger <george@mvista.com>]

evan@coolrunningconcepts.com wrote:
> I was thinking about benchmarking, profiling, and various other applications
> that might need frequent access to the current time.  Polling timers or
> frequent timer signal delivery both seem like there would be a lot of overhead.
>  I was thinking it would be nice if you could just read the time information
> without making an OS call.
> 
> I figure the kernel keeps accurate records of current time information and the
> values of various timers.  I then had the idea that one could have a /dev or
> maybe a /proc entry that would allow you to mmap() the kernel records (read
> only) and then you could read this information right from the kernel without
> any overhead.
> 

Your are describing the vsyscall.  John Stultz and company are actively working on this as we speak. 
  If memory serves, it is already available on some platforms.

-- 
George Anzinger   george@mvista.com
HRT (High-res-timers):  http://sourceforge.net/projects/high-res-timers/