Messages in this thread | | | Date | Wed, 29 May 2019 09:28:55 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/9] perf/x86/intel: Basic support for metrics counters |
| |
On Tue, May 28, 2019 at 02:21:49PM -0400, Liang, Kan wrote: > > > On 5/28/2019 8:15 AM, Peter Zijlstra wrote: > > On Tue, May 21, 2019 at 02:40:48PM -0700, kan.liang@linux.intel.com wrote: > > > +/* > > > + * We model PERF_METRICS as more magic fixed-mode PMCs, one for each metric > > > + * and another for the whole slots counter > > > + * > > > + * Internally they all map to Fixed Ctr 3 (SLOTS), and allocate PERF_METRICS > > > + * as an extra_reg. PERF_METRICS has no own configuration, but we fill in > > > + * the configuration of FxCtr3 to enforce that all the shared users of SLOTS > > > + * have the same configuration. > > > + */ > > > +#define INTEL_PMC_IDX_FIXED_METRIC_BASE (INTEL_PMC_IDX_FIXED + 17) > > > +#define INTEL_PMC_IDX_TD_RETIRING (INTEL_PMC_IDX_FIXED_METRIC_BASE + 0) > > > +#define INTEL_PMC_IDX_TD_BAD_SPEC (INTEL_PMC_IDX_FIXED_METRIC_BASE + 1) > > > +#define INTEL_PMC_IDX_TD_FE_BOUND (INTEL_PMC_IDX_FIXED_METRIC_BASE + 2) > > > +#define INTEL_PMC_IDX_TD_BE_BOUND (INTEL_PMC_IDX_FIXED_METRIC_BASE + 3) > > > +#define INTEL_PMC_MSK_ANY_SLOTS ((0xfull << INTEL_PMC_IDX_FIXED_METRIC_BASE) | \ > > > + INTEL_PMC_MSK_FIXED_SLOTS) > > > +static inline bool is_metric_idx(int idx) > > > +{ > > > + return idx >= INTEL_PMC_IDX_FIXED_METRIC_BASE && idx <= INTEL_PMC_IDX_TD_BE_BOUND; > > > +} > > > > Something like: > > > > return (idx >> INTEL_PMC_IDX_FIXED_METRIC_BASE) & 0xf; > > > > might be faster code... (if it wasn't for 64bit literals being a pain, > > it could be a simple test instruction). > > > > is_metric_idx() is not a mask. It's to check if the idx between 49 and 52.
blergh, indeed. Check that it compiles into a single branch though, if it gets that wrong it needs hand holding.
One way would be to make these 48-51 and put BTS as 52, and then you do have a mask.
Another way would be to write it as:
(unsigned)(idx - INTEL_PMC_IDX_FIXED_METRIC_BASE) < 4;
| |