----- "Luciano Chavez" <lnx1138@xxxxxxxxxxxxxxxxxx> wrote: > Hi Dave, > > Thinking about backward compatibility, would displaying "ONLINE CPUS" > still seem OK for the case where kernel_init() finds the smp_num_cpus > symbol (as for a 2.4 kernel)? Before there were the various cpu maps, I > think smp_num_cpus was analogous to the possible cpus as opposed to > online. I can see this requiring some thought as to what CPUS in the > output means when you have various different maps now (online, possible, > and present). That being said, it would be good to leave no doubt and > explicitly state the count is for the present or online CPUS with the > latter being my suggestion. > > I forgot to mention that I suspect the problem I mentioned before would > get stranger for POWER7 which offers 4 threads per core. I didn't have > access to a POWER7 machine to see just what it would do if we tried > disabling SMT as before but it follows the same pattern the count > displayed would be way off from the online count. I just ran through a bunch of stashed dumpfiles I have on hand, and it gets even murkier when dealing with Xen or KVM kernels, because as part of the post-crash shutdown (or forced dump), all but one of the cpus may be taken "offline". So even though there may be 4 vcpus, and crash correctly shows 4 "CPUS", the cpu_online_map shows only one cpu bit. So if we went ahead and displayed a number based upon the cpu_online_map, it would completely misleading. Incorrect actually... Dave -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
