On Fri, Mar 02, 2018 at 11:18:10AM +0100, Rafael J. Wysocki wrote: > On Fri, Mar 2, 2018 at 10:41 AM, Du, Changbin <changbin...@intel.com> wrote: > >> >> That rather isn't the case if negative values are ever passed to the > >> >> tracepoint, right? > >> >> > >> > yes. > >> >> Which seems to be the reason why you want to make this change, isn't it? > >> >> > >> > yes, to improve readability. > >> > > >> >> So maybe fix the code using the tracepoint(s) to avoid passing > >> >> negative values to it(them)? > >> > For cpu_idle event, [0, CPUIDLE_STATE_MAX) are used to index the idle > >> > state arrary, > >> > so I think a appropriate value for PWR_EVENT_EXIT is -1 (defined in > >> > include/trace/events/power.h). > >> > Or do you have a better idea? Thanks! > >> > >> Sorry, I'm not sure what you mean. > >> > >> I'm saying that the code using the CPU PM tracepoints is not expected > >> to pass -1 as the CPU number to them. IOW, neither -1 nor its UL > >> representation should ever appear in the output of these tracepoints. > >> If that happens, it is a problem with the code using the tracepoints > >> which needs to be fixed. Users should not see any of these values. > > > > This patch only changed 'state' field but cpuid. For cpu_idle event, > > 'state' is > > singned value, but for cpu_frequency it is unsinged. > > The cpuid is always unsinged value. So no one passes -1 as CPU number. > > You are right, 'state' not 'cpuid', sorry. > > Negative 'state' should not be passed to these tracepoints too, though.
The current situtation is that 'state' can be negative for event cpu_idle :(. This is why I made this change. -- Thanks, Changbin Du
