Re: [libvirt] [RFC] New API to retrieve node CPU map
On 10/11/2012 02:27 PM, Eric Blake wrote:
That starts to feel rather complex.
well :-)
On the other hand, you have a point that returning maplen (number of
bytes allocated in the map) does NOT tell you how many cpus are online
without doing a population count of the result; worse, it cannot tell
you how many cpus are offline (a maplen of 1 is returned whether I have
4 cpus or 8 cpus, so if the map contains the value 0xb, does that mean I
had a 4 cpu machine with cpu2 off, or an 8 cpu machine with cpu2 and
cpu4-7 off?). So allowing the user to optionally ask how many cpus are
online or offline might indeed also be useful, in addition to the maplen
needed to return the bitmap.
I actually thought of returning the number of CPUs, i.e. relevant bits which
of course makes either 'online' or 'offline' redundant.
The maplen - if of interest - can be computed by VIR_CPU_MAPLEN.
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