On 5/20/20 11:50 PM, Ian Rogers wrote: > Metric groups contain metrics. Metrics create groups of events to > ideally be scheduled together. Often metrics refer to the same events, > for example, a cache hit and cache miss rate. Using separate event > groups means these metrics are multiplexed at different times and the > counts don't sum to 100%. More multiplexing also decreases the > accuracy of the measurement. > > This change orders metrics from groups or the command line, so that > the ones with the most events are set up first. Later metrics see if > groups already provide their events, and reuse them if > possible. Unnecessary events and groups are eliminated. > > The option --metric-no-group is added so that metrics aren't placed in > groups. This affects multiplexing and may increase sharing. > > The option --metric-mo-merge is added and with this option the > existing grouping behavior is preserved. > > Using skylakex metrics I ran the following shell code to count the > number of events for each metric group (this ignores metric groups > with a single metric, and one of the duplicated TopdownL1 and > TopDownL1 groups): > > for i in all Branches BrMispredicts Cache_Misses FLOPS Instruction_Type Memory_BW Pipeline Power SMT Summary TopdownL1 TopdownL1_SMT > do > echo Metric group: $i > echo -n " - No merging (old default, now --metric-no-merge): " > /tmp/perf/perf stat -a --metric-no-merge -M $i sleep 1 2>&1 | grep -v "^ *#" | egrep " +[0-9,.]+ [^s]" | wc -l > echo -n " - Merging over metrics (new default) : " > /tmp/perf/perf stat -a -M $i sleep 1 2>&1 | grep -v "^ *#" | egrep " +[0-9,.]+ [^s]"|wc -l > echo -n " - No event groups and merging (--metric-no-group): " > /tmp/perf/perf stat -a --metric-no-group -M $i sleep 1 2>&1 | grep -v "^ *#" | egrep " +[0-9,.]+ [^s]"|wc -l > done > > Metric group: all > - No merging (old default, now --metric-no-merge): 193 > - Merging over metrics (new default) : 142 > - No event groups and merging (--metric-no-group): 84 > Metric group: Branches > - No merging (old default, now --metric-no-merge): 8 > - Merging over metrics (new default) : 8 > - No event groups and merging (--metric-no-group): 4 > Metric group: BrMispredicts > - No merging (old default, now --metric-no-merge): 11 > - Merging over metrics (new default) : 11 > - No event groups and merging (--metric-no-group): 10 > Metric group: Cache_Misses > - No merging (old default, now --metric-no-merge): 11 > - Merging over metrics (new default) : 9 > - No event groups and merging (--metric-no-group): 6 > Metric group: FLOPS > - No merging (old default, now --metric-no-merge): 18 > - Merging over metrics (new default) : 10 > - No event groups and merging (--metric-no-group): 10 > Metric group: Instruction_Type > - No merging (old default, now --metric-no-merge): 6 > - Merging over metrics (new default) : 6 > - No event groups and merging (--metric-no-group): 4 > Metric group: Pipeline > - No merging (old default, now --metric-no-merge): 6 > - Merging over metrics (new default) : 6 > - No event groups and merging (--metric-no-group): 5 > Metric group: Power > - No merging (old default, now --metric-no-merge): 16 > - Merging over metrics (new default) : 16 > - No event groups and merging (--metric-no-group): 10 > Metric group: SMT > - No merging (old default, now --metric-no-merge): 11 > - Merging over metrics (new default) : 8 > - No event groups and merging (--metric-no-group): 7 > Metric group: Summary > - No merging (old default, now --metric-no-merge): 19 > - Merging over metrics (new default) : 17 > - No event groups and merging (--metric-no-group): 17 > Metric group: TopdownL1 > - No merging (old default, now --metric-no-merge): 16 > - Merging over metrics (new default) : 7 > - No event groups and merging (--metric-no-group): 7 > Metric group: TopdownL1_SMT > - No merging (old default, now --metric-no-merge): 24 > - Merging over metrics (new default) : 7 > - No event groups and merging (--metric-no-group): 7 > > There are 5 out of 12 metric groups where no events are shared, such > as Power, however, disabling grouping of events always reduces the > number of events. > > The result for Memory_BW needs explanation: > > Metric group: Memory_BW > - No merging (old default, now --metric-no-merge): 9 > - Merging over metrics (new default) : 5 > - No event groups and merging (--metric-no-group): 11 > > Both with and without merging the groups fail to be set up and so the > event counts here are for broken metrics. The --metric-no-group number > is accurate as all the events are scheduled. Ideally a constraint > would be added for these metrics in the json code to avoid grouping. > > v2. rebases on kernel/git/acme/linux.git branch tmp.perf/core, fixes a > missing comma with metric lists (reported-by Jiri Olsa > <jolsa@xxxxxxxxxx>) and adds early returns to metricgroup__add_metric > (suggested-by Jiri Olsa). > > v1. was prepared on kernel/git/acme/linux.git branch tmp.perf/core > > Compared to RFC v3: fix a bug where unnecessary commas were passed to > parse-events and were echoed. Fix a bug where the same event could be > matched more than once with --metric-no-group, causing there to be > events missing. > https://lore.kernel.org/lkml/20200508053629.210324-1-irogers@xxxxxxxxxx/ > > Ian Rogers (7): > perf metricgroup: Always place duration_time last > perf metricgroup: Use early return in add_metric > perf metricgroup: Delay events string creation > perf metricgroup: Order event groups by size > perf metricgroup: Remove duped metric group events > perf metricgroup: Add options to not group or merge > perf metricgroup: Remove unnecessary ',' from events > Reviewd-By: Kajol Jain <kjain@xxxxxxxxxxxxx> Tested-By: Kajol Jain <kjain@xxxxxxxxxxxxx> ( Tested it to see behavior with some metric groups in both x86 and Power machine) Thanks, Kajol Jain > tools/perf/Documentation/perf-stat.txt | 19 ++ > tools/perf/builtin-stat.c | 11 +- > tools/perf/util/metricgroup.c | 239 ++++++++++++++++++------- > tools/perf/util/metricgroup.h | 6 +- > tools/perf/util/stat.h | 2 + > 5 files changed, 207 insertions(+), 70 deletions(-) >
