On 03/05/2010 12:06 PM, Chris Lalancette wrote:
The current code for "nodeinfo" is pretty naive about socket and thread information. To determine the sockets, it just takes the number of cpus and divides by the number of cores. For the thread count, it always sets it to 1. With more recent Intel machines, however, hyperthreading is again an option, meaning that these heuristics no longer work and give bogus numbers.
I noticed this has already been committed, but here are some further ideas for improvement:
+#define CPU_SYS_PATH "/sys/devices/system/cpu" ... + if (virAsprintf(&path, "%s/cpu%d/topology/thread_siblings", CPU_SYS_PATH, + cpu) < 0) {
Do more work at compile-time and less at runtime, by using string concatenation, as in: virAsprintf(&path, CPU_SYS_PATH "/cpu%d/topology/thread_siblings", cpu)
+ +static int parse_socket(int cpu) +{
Several tools (such as ctag, or even more simply, 'git grep "^func"') work better if all function implementations are listed with split lines, such that the function name starts at the first column: static int parse_socket(int cpu) { Would it be worth a global cleanup patch that does this throughout libvirt, rather than the current ad hoc mix in declaration styles?
+ nodeinfo->nodes = nodeinfo->cores = 1;
/* NB: It is impossible to fill our nodes, since cpuinfo * has not knowledge of NUMA nodes */
s/not/no/ -- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org