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.