Hi Sudeep, > > Please have a look at these two commits which should describe why things > > are as they are on s390: > > > > 881730ad365130f64b5c70c40904b04eb3b79de3 > > "s390/cache: expose cpu cache topology via sysfs" > > 6668022c7bde3fdc96d3d257294a7216c7a46829 > > "s390/cache: add cpu cache information to /proc/cpuinfo" > > > > I need your help to get few things clarified. > > IIUC, I see that shared caches are not exposed via sysfs but there are exposed > through /proc/cpuinfo, right ? Yes. > If yes, based on your above statement, shared > cpus are may not be system-wide, then how can /proc/cpuinfo show shared > cache info. /proc/cpuinfo shows the information of the underlying hardware but we cannot tell which second level (virtual) cpus share which caches. There simply is no such interface available. Also, if there would be such an interface, it would be only valid until the hypervisor decides to schedule a virtual cpu on a different physical cpu; which in turn would mean that we would have to update the cpu maps all the time. In order to avoid all those games, we decided to only expose cpu private caches via sysfs, so we obviously have static cpu maps. However since the physical cache information may be of interest for a guest operating system there is the second interface /proc/cpuinfo which provides this. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
