On 16.11.2013 0:15, Alexander Graf wrote:
Am 15.11.2013 um 00:12 schrieb Alexey Kardashevskiy <address@hidden>:
At the moment only a whole CPU core can be assigned to a KVM. Since
POWER7/8 support several threads per core, we want all threads of a core
to go to the same KVM so every time we run QEMU with -enable-kvm on
POWER, we have to add -smp X,threads=(4|8)" (4 for POWER7 and
8 for POWER8).
This patch tries to read smp_threads number from an accelerator and
falls back to the default value (1) if the accelerator did not care
to change it.
Signed-off-by: Alexey Kardashevskiy <address@hidden>
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(!!!)
The usual question - what would be the normal way of doing this?
What does this patch break? I cannot think of anything right now.
Is this really what the user wants? On p7 you can run in no-smt, smt2
and smt4 mode. Today we simply default to no-smt. Changing defaults
is usually a bad thing.
Defaulting to 1 thread on P7 is a bad thing (other threads stay unused -
what is good about this?) and the only reason which I know why it is
still threads=1 is that it is hard to make a patch for upstream to
change this default.