diff options
Diffstat (limited to 'tools/perf/Documentation/perf-stat.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-stat.txt | 155 |
1 files changed, 126 insertions, 29 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index c06c341e72b9..1a766d4a2233 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -39,7 +39,7 @@ report:: - a raw PMU event in the form of rN where N is a hexadecimal value that represents the raw register encoding with the layout of the event control registers as described by entries in - /sys/bus/event_sources/devices/cpu/format/*. + /sys/bus/event_source/devices/cpu/format/*. - a symbolic or raw PMU event followed by an optional colon and a list of event modifiers, e.g., cpu-cycles:p. See the @@ -308,6 +308,22 @@ use --per-die in addition to -a. (system-wide). The output includes the die number and the number of online processors on that die. This is useful to gauge the amount of aggregation. +--per-cluster:: +Aggregate counts per processor cluster for system-wide mode measurement. This +is a useful mode to detect imbalance between clusters. To enable this mode, +use --per-cluster in addition to -a. (system-wide). The output includes the +cluster number and the number of online processors on that cluster. This is +useful to gauge the amount of aggregation. The information of cluster ID and +related CPUs can be gotten from /sys/devices/system/cpu/cpuX/topology/cluster_{id, cpus}. + +--per-cache:: +Aggregate counts per cache instance for system-wide mode measurements. By +default, the aggregation happens for the cache level at the highest index +in the system. To specify a particular level, mention the cache level +alongside the option in the format [Ll][1-9][0-9]*. For example: +Using option "--per-cache=l3" or "--per-cache=L3" will aggregate the +information at the boundary of the level 3 cache in the system. + --per-core:: Aggregate counts per physical processor for system-wide mode measurements. This is a useful mode to detect imbalance between physical cores. To enable this mode, @@ -353,9 +369,18 @@ small group that need not have multiplexing is lowered. This option forbids the event merging logic from sharing events between groups and may be used to increase accuracy in this case. +--metric-no-threshold:: +Metric thresholds may increase the number of events necessary to +compute whether a metric has exceeded its threshold expression. This +may not be desirable, for example, as the events can introduce +multiplexing. This option disables the adding of threshold expression +events for a metric. However, if there are sufficient events to +compute the threshold then the threshold is still computed and used to +color the metric's computed value. + --quiet:: -Don't print output. This is useful with perf stat record below to only -write data to the perf.data file. +Don't print output, warnings or messages. This is useful with perf stat +record below to only write data to the perf.data file. STAT RECORD ----------- @@ -379,6 +404,17 @@ Aggregate counts per processor socket for system-wide mode measurements. --per-die:: Aggregate counts per processor die for system-wide mode measurements. +--per-cluster:: +Aggregate counts perf processor cluster for system-wide mode measurements. + +--per-cache:: +Aggregate counts per cache instance for system-wide mode measurements. By +default, the aggregation happens for the cache level at the highest index +in the system. To specify a particular level, mention the cache level +alongside the option in the format [Ll][1-9][0-9]*. For example: Using +option "--per-cache=l3" or "--per-cache=L3" will aggregate the +information at the boundary of the level 3 cache in the system. + --per-core:: Aggregate counts per physical processor for system-wide mode measurements. @@ -389,15 +425,48 @@ For a group all metrics from the group are added. The events from the metrics are automatically measured. See perf list output for the possible metrics and metricgroups. + When threshold information is available for a metric, the + color red is used to signify a metric has exceeded a threshold + while green shows it hasn't. The default color means that + no threshold information was available or the threshold + couldn't be computed. + -A:: --no-aggr:: -Do not aggregate counts across all monitored CPUs. +--no-merge:: +Do not aggregate/merge counts across monitored CPUs or PMUs. + +When multiple events are created from a single event specification, +stat will, by default, aggregate the event counts and show the result +in a single row. This option disables that behavior and shows the +individual events and counts. + +Multiple events are created from a single event specification when: + +1. PID monitoring isn't requested and the system has more than one + CPU. For example, a system with 8 SMT threads will have one event + opened on each thread and aggregation is performed across them. + +2. Prefix or glob wildcard matching is used for the PMU name. For + example, multiple memory controller PMUs may exist typically with a + suffix of _0, _1, etc. By default the event counts will all be + combined if the PMU is specified without the suffix such as + uncore_imc rather than uncore_imc_0. + +3. Aliases, which are listed immediately after the Kernel PMU events + by perf list, are used. + +--hybrid-merge:: +Merge core event counts from all core PMUs. In hybrid or big.LITTLE +systems by default each core PMU will report its count +separately. This option forces core PMU counts to be combined to give +a behavior closer to having a single CPU type in the system. --topdown:: -Print complete top-down metrics supported by the CPU. This allows to -determine bottle necks in the CPU pipeline for CPU bound workloads, -by breaking the cycles consumed down into frontend bound, backend bound, -bad speculation and retiring. +Print top-down metrics supported by the CPU. This allows to determine +bottle necks in the CPU pipeline for CPU bound workloads, by breaking +the cycles consumed down into frontend bound, backend bound, bad +speculation and retiring. Frontend bound means that the CPU cannot fetch and decode instructions fast enough. Backend bound means that computation or memory access is the bottle @@ -429,31 +498,36 @@ To interpret the results it is usually needed to know on which CPUs the workload runs on. If needed the CPUs can be forced using taskset. ---td-level:: -Print the top-down statistics that equal to or lower than the input level. -It allows users to print the interested top-down metrics level instead of -the complete top-down metrics. +--record-tpebs:: +Enable automatic sampling on Intel TPEBS retire_latency events (event with :R +modifier). Without this option, perf would not capture dynamic retire_latency +at runtime. Currently, a zero value is assigned to the retire_latency event when +this option is not set. The TPEBS hardware feature starts from Intel Granite +Rapids microarchitecture. This option only exists in X86_64 and is meaningful on +Intel platforms with TPEBS feature. + +--tpebs-mode=[mean|min|max|last]:: +Set how retirement latency events have their sample times +combined. The default "mean" gives the average of retirement +latency. "min" or "max" give the smallest or largest retirment latency +times respectively. "last" uses the last retirment latency sample's +time. -The availability of the top-down metrics level depends on the hardware. For -example, Ice Lake only supports L1 top-down metrics. The Sapphire Rapids -supports both L1 and L2 top-down metrics. +--td-level:: +Print the top-down statistics that equal the input level. It allows +users to print the interested top-down metrics level instead of the +level 1 top-down metrics. + +As the higher levels gather more metrics and use more counters they +will be less accurate. By convention a metric can be examined by +appending '_group' to it and this will increase accuracy compared to +gathering all metrics for a level. For example, level 1 analysis may +highlight 'tma_frontend_bound'. This metric may be drilled into with +'tma_frontend_bound_group' with +'perf stat -M tma_frontend_bound_group...'. -Default: 0 means the max level that the current hardware support. Error out if the input is higher than the supported max level. ---no-merge:: -Do not merge results from same PMUs. - -When multiple events are created from a single event specification, -stat will, by default, aggregate the event counts and show the result -in a single row. This option disables that behavior and shows -the individual events and counts. - -Multiple events are created from a single event specification when: -1. Prefix or glob matching is used for the PMU name. -2. Aliases, which are listed immediately after the Kernel PMU events - by perf list, are used. - --smi-cost:: Measure SMI cost if msr/aperf/ and msr/smi/ events are supported. @@ -560,6 +634,29 @@ Additional metrics may be printed with all earlier fields being empty. include::intel-hybrid.txt[] +JSON FORMAT +----------- + +With -j, perf stat is able to print out a JSON format output +that can be used for parsing. + +- interval : optional timestamp in fractions of second (with -I) +- optional aggregate options: + - core : core identifier (with --per-core) + - die : die identifier (with --per-die) + - socket : socket identifier (with --per-socket) + - node : node identifier (with --per-node) + - thread : thread identifier (with --per-thread) +- counters : number of aggregated PMU counters +- counter-value : counter value +- unit : unit of the counter value or empty +- event : event name +- variance : optional variance if multiple values are collected (with -r) +- event-runtime : run time of the event +- pcnt-running : percentage of time the event was running +- metric-value : optional metric value +- metric-unit : optional unit of metric + SEE ALSO -------- linkperf:perf-top[1], linkperf:perf-list[1] |