Re: [PATCH 3/6] perf record: add time-of-day option

Peter Zijlstra
2011-03-01T16:35:47Z

On Tue, 2011-03-01 at 09:09 -0700, David Ahern wrote:
>
> I did not code it create samples of a realtime-clock event; I coded it
> to add an event to the stream on demand -- whatever event the fd is
> tied to.
>
>
Well yes, but aside from you and the realtime clock stuff, who'd ever
want to do this particular thing?

I'd much rather expose the whole
local_clock()/perf_clock()/trace_clock() (should all be the same anyway)
as a posix clock using CLOCK_TRACING or whatever would be an appropriate
name.

[ Since the whole thing is NMI safe it should be well possible to make a
VDSO version as well. ]

Anyway, once its visible as a posix clock you can sync up from
userspace. And this clock is indeed wanted for other things too, like
user-space tracing etc.