Re: [Xen-devel] write_tsc in a PV domain?

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 31/08/2009 22:06, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:

> A thousand cycles to trap, decode, call get_s_time,
> and return seems astoundingly good?  Probably it's
> faster than a vmexit because there's so much less state
> to save.  But still it's 15x slower than a raw rdtsc.

A kernel trap used to take about a microsecond. Maybe it has got faster on
new processors.

 -- Keir



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