This fix tries to address issues raised in #23768 where the CPU count
is not updated after cpu ho-plugging.
This fix follows the suggestion from #23768 and replace go's `runtime.NumCPU()`
with `sysconf(_SC_NPROCESSORS_ONLN)` so that correct CPU count could
be obtained even after CPU hot-plugging.
This fix is tested manually, as is suggested in #23768.
This fix fixes#23768.
The NumCPU() in Linux is based on @wmark 's implementation.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: 8b2383f5c1108c590928c0e6c57f1f0aa0dd36f6
Component: engine
bde674f465