Re: [libvirt] [Qemu-devel] [PATCH v2] vl.c: Support multiple CPU ranges on -numa option
Il 28/02/2013 14:41, Anthony Liguori ha scritto:
This is certainly ambiguous. Does this mean that you have a single cpu
for the node (VCPU 4) or does it mean the node have 4 cpus (presumably
ranged 0-3).
Given that ambiguity the following:
qemu -numa node,nodeid=2,cpus=4,cpus=8
Does help the situation. A reasonable person could assume that cpus=8
overrides the previous cpus=4 (as it does elsewhere in QEMU) and
therefore assume they were creating a node with 8 CPUS (0-7) instead of
two cpus. However:
qemu -numa node,nodeid=2,cpus=4:8
Is much less ambiguous. Granted, it's not immediately obvious whether
this is a range specification or a disjoint specification but it's more
clear than the previous syntax.
This makes your point clear, but it sounds a bit artificial. "4" or
"8"
would never appear alone. You would likely have something like
-numa node,nodeid=0,cpus=0,cpus=12 \
-numa node,nodeid=1,cpus=1,cpus=13 \
-numa node,nodeid=2,cpus=2,cpus=14 \
-numa node,nodeid=3,cpus=3,cpus=15 \
-numa node,nodeid=4,cpus=4,cpus=8
which would make the syntax much more obvious.
Something like 4:8 would be rather unclear actually, because both numbes
are even. Given "-numa node,nodeid=2,cpus=4:8" out of context, I would
guess that 4:8 is [4,8) where the upper-bound is excluded for some
reason. Of course context would clear it up, but that also applies to
cpus=foo,cpus=bar.
Paolo