Messages in this thread | | | Subject | Re: Timer idea | From | john stultz <> | Date | Tue, 15 Nov 2005 11:12:20 -0800 |
| |
On Tue, 2005-11-15 at 10:58 -0800, George Anzinger wrote: > 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.
Yep. x86-64 already supports this as does ppc64 via vsyscall/VDSOs. ia64 has a different variant on it as well (fast syscalls).
thanks -john
- 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/
| |