RE: [Xen-devel] [RFC] Physical hot-add cpus and TSC

[Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>]

> b) With the patch:
> After add:
> (XEN) TSC marked as reliable, warp = 407 (count=12)
> (XEN) TSC marked as reliable, warp = 444 (count=17)
> (XEN) TSC marked as reliable, warp = 525 (count=19)

Hi Yunhong --

Does this continue to grow?  I'm concerned that
the hot-added CPU might be skewing as well?
I didn't think this was possible with an Invariant
TSC machine but maybe something in the hot-add
isolation electronics changes the characteristics
of the clock signal?

Please try:

for i in {0..1000}; do xm debug-key t; sleep 3; done; \
xm dmesg | tail

then wait an hour, and see how large the warp is.
Hopefully the trend (407,444,525) is a coincidence.

Thanks,
Dan

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