On Tue, Oct 16, 2018 at 04:34:05PM +0000, Song Liu wrote: > >> 3. perf_event_pmu_context owns RB tree of events. Since we don't > >> need rotation across multiple hardware PMUs, the rotation is > >> within same perf_event_pmu_context. > > > > By keeping the RB trees in perf_event_context, we get bigger trees, > > which is more efficient (log(n+m) < log(n) + log(m)) > > > > Also, specifically, it means we only need a single merge sort / > > iteration to schedule in a full context, instead of (again) doing 'n' of > > them. > > > > Also, given a context and a pmu, it is cheaper for finding the relevant > > events; this is needed for big.little for instance. Something the > > proposed patch doesn't fully flesh out. > > Would it be faster if we add a perf_event_pmu_context pointer to the > perf_event?
+ pmu_ctx = find_get_pmu_context(pmu, ctx, event); + if (IS_ERR(pmu_ctx)) { + err = PTR_ERR(pmu_ctx); + goto err_locked; + } + event->pmu_ctx = pmu_ctx; Like that?