perf/Documentation/topdown.txt

2 -----------------------------------
5 methology to break down CPU pipeline execution into 4 bottlenecks:
10 Traditionally this was implemented by events in generic counters
13 perf stat --topdown implements this.
15 Full Top Down includes more levels that can break down the
24 fixed counters and do not require generic counters. This allows
27 % perf stat -a --topdown -I1000
64 metric event, and allow user programs to read the performance counters.
94 int slots_fd = perf_event_open(&slots, 0, -1, -1, 0);
109 int metrics_fd = perf_event_open(&metrics, 0, -1, slots_fd, 0);
120 #define RDPMC_FIXED	(1 << 30)	/* return fixed counters */
121 #define RDPMC_METRIC	(1 << 29)	/* return metric counters */
188 	retiring_slots = GET_METRIC(metric_b, 0) * slots_b - retiring_slots_a
189 	bad_spec_slots = GET_METRIC(metric_b, 1) * slots_b - bad_spec_slots_a
190 	fe_bound_slots = GET_METRIC(metric_b, 2) * slots_b - fe_bound_slots_a
191 	be_bound_slots = GET_METRIC(metric_b, 3) * slots_b - be_bound_slots_a
196 	slots_delta = slots_b - slots_a
208 Resetting metrics counters
213 fraction bit shrinks. So the counters need to be reset regularly.
219 When using perf stat it is recommended to always use the -I option,
222 	perf stat -I 1000 --topdown ...
237 Four pseudo TopDown metric events are exposed for the end-users,
238 topdown-retiring, topdown-bad-spec, topdown-fe-bound and topdown-be-bound.
241 - All the TopDown metric events must be in a group with the SLOTS event.
242 - The SLOTS event must be the leader of the group.
243 - The PERF_FORMAT_GROUP flag must be applied for each TopDown metric
249 For example, perf record -e '{slots, $sampling_event, topdown-retiring}:S'
252 [1] https://software.intel.com/en-us/top-down-microarchitecture-analysis-method-win
253 [2] https://github.com/andikleen/pmu-tools/wiki/toplev-manual
254 [3] https://software.intel.com/en-us/intel-vtune-amplifier-xe
255 [4] https://github.com/andikleen/pmu-tools/tree/master/jevents
256 [5] https://sites.google.com/site/analysismethods/yasin-pubs