Messages in this thread | | | From | "H. Peter Anvin" <> | Subject | Re: [PATCH][2.4.20-pre5] non syscall gettimeofday | Date | 5 Sep 2002 16:38:35 -0700 |
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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.
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