On Tue, Nov 21, 2017 at 04:30:09PM +0800, zhangmengting wrote: SNIP
> > > > also I think the precise level is not generic for all the events, > > > > so you should check it for specific perf_event_attr later, when > > > > the attr is ready, not in modifier parsing > > > You are right, and I would check it for specific perf_event_attr. > > > > > > BTW, I have a question. If the user-specified precise_ip is greater than > > > the > > > max precise_ip, I wonder > > > whether it is better to adjust the user-specified precise_ip to the > > > maximum > > > available. > > no, I think that user defined precise level should stay the > > way the user wants it.. we don't want more angry users ;-) > > Humm, I am sorry for being unclear. > If the user defined precise level is greater than the max precise level, > I think there are two ways to deal with it. > 1. return EINVAL to indicate the invalid precise_ip setting; and warn user about the reason > 2. adjust to the max precise level available and give message to indicate > the adjustment. we do that (or should) only if the precise_ip is not defined by user because we want the max precise level by default > Since we should check user-defined precise level in perf_evsel__config(), > when the attr is ready, I think there is a problem with method 1, if we keep > the > user defined precise level stay the way the user wants it. > > With method 1, we have to let perf_evsel__config() return value and show > errno. > And this change will affect many related functions, such as > perf_evlist__config(), and files. > > With method 2, we don't need to change the return type of > perf_evsel__config(). > > Am I right? not sure.. let's discuss over the code changes jirka
