On Tue, Jun 30, 2020 at 11:36:29AM -0400, Liang, Kan wrote: > > Why keep the full CPUID leaf here? What's wrong with something like: > > > > unsigned int lbr_depth_mask:8; > > unsigned int lbr_deep_c_reset:1; > > unsigned int lbr_lip:1; > > unsigned int lbr_cpl:1; > > unsigned int lbr_filter:1; > > unsigned int lbr_call_stack:1; > > unsigned int lbr_mispred:1; > > unsigned int lbr_timed_lbr:1; > > unsigned int lbr_br_type:1; > > > > That's only 2 bytes, instead of 24. > > Yes, it can save the space. > I will add some codes in patch 14 to initialize these items in > intel_pmu_arch_lbr_init().
It also makes stuff like: > + if (!x86_pmu.lbr_ebx.split.lbr_cpl || > + !x86_pmu.lbr_ebx.split.lbr_filter || > + !x86_pmu.lbr_ebx.split.lbr_call_stack) eminently more readable.
