Le 27/11/2018 à 00:01, Segher Boessenkool via cfarm-users a écrit : > >> Ansible parses /proc/cpuinfo: >> >> >> https://github.com/ansible/ansible/blob/devel/lib/ansible/module_utils/facts/hardware/linux.py#L181 >> >> Do you know how lscpu gets its information? > It uses /proc/cpuinfo, and /sys/devices/system/cpu/**, and > /sys/devices/system/node/node*/cpumap. Says strace. > > Maybe /sys/devices/system/cpu/cpu*/topology/thread_siblings is where it > finds what things really are cores and what things are threads? The source > will tell (but who knows what lscpu does is the most proper either!) > > Anyway, $KERNEL_SRC/Documentation/ABI/testing/sysfs-devices-system-cpu > and $KERNEL_SRC/Documentation/cputopology.txt should help.
Yes thread_siblings is where you can find the list of hardware threads in the same core on Linux. You'd basically count the number of different unique values in cpu/cpu*/thread_siblings to get the number of cores. Instead of hardwiring Linux-specific things, many projects now just use hwloc [1] to get such kind of topology information in a portable way (that's what I use cfarm for). On the command-line, you'd just do "hwloc-calc -N core all" to get the number of cores, but there's also a C API to do that. Brice [1] https://www.open-mpi.org/projects/hwloc/ _______________________________________________ cfarm-users mailing list cfarm-users@lists.tetaneutral.net https://lists.tetaneutral.net/listinfo/cfarm-users
