Re: [PATCH] RFC x86_64 more accurate KSTK_ESP implementation

[Andi Kleen]

Ingo Molnar <mingo@xxxxxxx> writes:
>
> I'd suggest a competely different method: why dont you use an IPI to 
> sample the SP whenever someone wants to read it from /proc and we see 
> that the task is running on a CPU right now?

Most of /proc tends to turn into a fast path when you run the right
monitoring tools unfortunately, which poll /proc at sometimes
quite high frequencies.

I suspect you'll slow something down significantly with this approach.

The only good way to avoid that would be to use a separate file, but again
if someone really wants it they can as well just use a ptrace()
based program from user space.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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