Some uncore metrics don't work as expected. For example, on
cascadelakex:
root@lkp-csl-2sp2:~# perf stat -M UNC_M_PMM_BANDWIDTH.TOTAL -a -- sleep 1
Performance counter stats for 'system wide':
1841092 unc_m_pmm_rpq_inserts
3680816 unc_m_pmm_wpq_inserts
1.001775055 seconds time elapsed
root@lkp-csl-2sp2:~# perf stat -M UNC_M_PMM_READ_LATENCY -a -- sleep 1
Performance counter stats for 'system wide':
860649746 unc_m_pmm_rpq_occupancy.all
1840557 unc_m_pmm_rpq_inserts
12790627455 unc_m_clockticks
1.001773348 seconds time elapsed
No metrics 'UNC_M_PMM_BANDWIDTH.TOTAL' or 'UNC_M_PMM_READ_LATENCY' are
reported.
The issue is, the case of an alias expanding to mulitple events is not
supported, typically the uncore events. (see comments in
find_evsel_group()).
For UNC_M_PMM_BANDWIDTH.TOTAL in above example, the expanded event group
is '{unc_m_pmm_rpq_inserts,unc_m_pmm_wpq_inserts}:W', but the actual
events passed to find_evsel_group are:
unc_m_pmm_rpq_inserts
unc_m_pmm_rpq_inserts
unc_m_pmm_rpq_inserts
unc_m_pmm_rpq_inserts
unc_m_pmm_rpq_inserts
unc_m_pmm_rpq_inserts
unc_m_pmm_wpq_inserts
unc_m_pmm_wpq_inserts
unc_m_pmm_wpq_inserts
unc_m_pmm_wpq_inserts
unc_m_pmm_wpq_inserts
unc_m_pmm_wpq_inserts
For this multiple events case, it's not supported well.
This patch introduces a new field 'metric_leader' in struct evsel. The
first event is considered as a metric leader. For the rest of same
events, they point to the first event via it's metric_leader field in
struct evsel.
This design is for adding the counting results of all same events to the
first event in group (the metric_leader).
With this patch,
root@lkp-csl-2sp2:~# perf stat -M UNC_M_PMM_BANDWIDTH.TOTAL -a -- sleep 1
Performance counter stats for 'system wide':
1842108 unc_m_pmm_rpq_inserts # 337.2 MB/sec UNC_M_PMM_BANDWIDTH.TOTAL
3682209 unc_m_pmm_wpq_inserts
1.001819706 seconds time elapsed
root@lkp-csl-2sp2:~# perf stat -M UNC_M_PMM_READ_LATENCY -a -- sleep 1
Performance counter stats for 'system wide':
861970685 unc_m_pmm_rpq_occupancy.all # 219.4 ns UNC_M_PMM_READ_LATENCY
1842772 unc_m_pmm_rpq_inserts
12790196356 unc_m_clockticks
1.001749103 seconds time elapsed
Now we can see the correct metrics 'UNC_M_PMM_BANDWIDTH.TOTAL' and
'UNC_M_PMM_READ_LATENCY'.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20190828055932.8269-5-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
f01642e491