Re: Timer idea

[George Anzinger]

evan@xxxxxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxx
HRT (High-res-timers):  http://sourceforge.net/projects/high-res-timers/
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