Followup to: <1031267553.10830.71.camel@dell_ss3.pdx.osdl.net>
By author: Stephen Hemminger <shemminger@osdl.org>
In newsgroup: linux.dev.kernel
>
> The following patch implements a shared memory interface to allow
> implementing gettimeofday (and other clock measurement) using the TSC
> counter on i386. On a 1.6G Xeon this reduces gettimeofday from 1.2 us
> per call to .17 us per call.
>
This sounds like a vsyscall. Since we have discussed vsyscalls on and
off without getting anywhere, I'd like to know how your implementation
does it -- the #1 proposal I think was to map in a page at 0xfffff000
and have the vsyscall code there.
Note that the vsyscall needs to bounce to a regular syscall if TSC
time/gettimeofday aren't available.
-hpa
-- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com> - 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/
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