diff options
Diffstat (limited to 'tools/perf/Documentation/perf-stat.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-stat.txt | 263 |
1 files changed, 234 insertions, 29 deletions
diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index b029ee728a0b..29756a87ab6f 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -9,8 +9,8 @@ SYNOPSIS -------- [verse] 'perf stat' [-e <EVENT> | --event=EVENT] [-a] <command> -'perf stat' [-e <EVENT> | --event=EVENT] [-a] -- <command> [<options>] -'perf stat' [-e <EVENT> | --event=EVENT] [-a] record [-o file] -- <command> [<options>] +'perf stat' [-e <EVENT> | --event=EVENT] [-a] \-- <command> [<options>] +'perf stat' [-e <EVENT> | --event=EVENT] [-a] record [-o file] \-- <command> [<options>] 'perf stat' report [-i file] DESCRIPTION @@ -36,8 +36,14 @@ report:: - a symbolic event name (use 'perf list' to list all events) - - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a - hexadecimal event descriptor. + - 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_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 + linkperf:perf-list[1] man page for details on event modifiers. - a symbolically formed event like 'pmu/param1=0x3,param2/' where param1 and param2 are defined as formats for the PMU in @@ -71,6 +77,37 @@ report:: --tid=<tid>:: stat events on existing thread id (comma separated list) +-b:: +--bpf-prog:: + stat events on existing bpf program id (comma separated list), + requiring root rights. bpftool-prog could be used to find program + id all bpf programs in the system. For example: + + # bpftool prog | head -n 1 + 17247: tracepoint name sys_enter tag 192d548b9d754067 gpl + + # perf stat -e cycles,instructions --bpf-prog 17247 --timeout 1000 + + Performance counter stats for 'BPF program(s) 17247': + + 85,967 cycles + 28,982 instructions # 0.34 insn per cycle + + 1.102235068 seconds time elapsed + +--bpf-counters:: + Use BPF programs to aggregate readings from perf_events. This + allows multiple perf-stat sessions that are counting the same metric (cycles, + instructions, etc.) to share hardware counters. + To use BPF programs on common events by default, use + "perf config stat.bpf-counter-events=<list_of_events>". + +--bpf-attr-map:: + With option "--bpf-counters", different perf-stat sessions share + information about shared BPF programs and maps via a pinned hashmap. + Use "--bpf-attr-map" to specify the path of this pinned hashmap. + The default path is /sys/fs/bpf/perf_attr_map. + ifdef::HAVE_LIBPFM[] --pfm-events events:: Select a PMU event using libpfm4 syntax (see http://perfmon2.sf.net) @@ -120,7 +157,10 @@ Do not aggregate counts across all monitored CPUs. -n:: --null:: - null run - don't start any counters +null run - Don't start any counters. + +This can be useful to measure just elapsed wall-clock time - or to assess the +raw overhead of perf stat itself, without running any counters. -v:: --verbose:: @@ -162,6 +202,12 @@ use '-e e1 -e e2 -G foo,foo' or just use '-e e1 -e e2 -G foo'. If wanting to monitor, say, 'cycles' for a cgroup and also for system wide, this command line can be used: 'perf stat -e cycles -G cgroup_name -a -e cycles'. +--for-each-cgroup name:: +Expand event list for each cgroup in "name" (allow multiple cgroups separated +by comma). It also support regex patterns to match multiple groups. This has same +effect that repeating -e option and -G option for each event x name. This option +cannot be used with -G/--cgroup option. + -o file:: --output file:: Print the output into the designated file. @@ -173,14 +219,55 @@ Append to the output file designated with the -o option. Ignored if -o is not sp Log output to fd, instead of stderr. Complementary to --output, and mutually exclusive with it. --append may be used here. Examples: - 3>results perf stat --log-fd 3 -- $cmd - 3>>results perf stat --log-fd 3 --append -- $cmd + 3>results perf stat --log-fd 3 \-- $cmd + 3>>results perf stat --log-fd 3 --append \-- $cmd + +--control=fifo:ctl-fifo[,ack-fifo]:: +--control=fd:ctl-fd[,ack-fd]:: +ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows. +Listen on ctl-fd descriptor for command to control measurement ('enable': enable events, +'disable': disable events). Measurements can be started with events disabled using +--delay=-1 option. Optionally send control command completion ('ack\n') to ack-fd descriptor +to synchronize with the controlling process. Example of bash shell script to enable and +disable events during measurements: + + #!/bin/bash + + ctl_dir=/tmp/ + + ctl_fifo=${ctl_dir}perf_ctl.fifo + test -p ${ctl_fifo} && unlink ${ctl_fifo} + mkfifo ${ctl_fifo} + exec {ctl_fd}<>${ctl_fifo} + + ctl_ack_fifo=${ctl_dir}perf_ctl_ack.fifo + test -p ${ctl_ack_fifo} && unlink ${ctl_ack_fifo} + mkfifo ${ctl_ack_fifo} + exec {ctl_fd_ack}<>${ctl_ack_fifo} + + perf stat -D -1 -e cpu-cycles -a -I 1000 \ + --control fd:${ctl_fd},${ctl_fd_ack} \ + \-- sleep 30 & + perf_pid=$! + + sleep 5 && echo 'enable' >&${ctl_fd} && read -u ${ctl_fd_ack} e1 && echo "enabled(${e1})" + sleep 10 && echo 'disable' >&${ctl_fd} && read -u ${ctl_fd_ack} d1 && echo "disabled(${d1})" + + exec {ctl_fd_ack}>&- + unlink ${ctl_ack_fifo} + + exec {ctl_fd}>&- + unlink ${ctl_fifo} + + wait -n ${perf_pid} + exit $? + --pre:: --post:: Pre and post measurement hooks, e.g.: -perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' -- make -s -j64 O=defconfig-build/ bzImage +perf stat --repeat 10 --null --sync --pre 'make -s O=defconfig-build/clean' \-- make -s -j64 O=defconfig-build/ bzImage -I msecs:: --interval-print msecs:: @@ -221,6 +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, @@ -238,8 +341,9 @@ mode, use --per-node in addition to -a. (system-wide). -D msecs:: --delay msecs:: -After starting the program, wait msecs before measuring. This is useful to -filter out the startup phase of the program, which is often very different. +After starting the program, wait msecs before measuring (-1: start with events +disabled). This is useful to filter out the startup phase of the program, +which is often very different. -T:: --transaction:: @@ -265,6 +369,19 @@ 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, warnings or messages. This is useful with perf stat +record below to only write data to the perf.data file. + STAT RECORD ----------- Stores stat data into perf data file. @@ -287,6 +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. @@ -295,17 +423,50 @@ Aggregate counts per physical processor for system-wide mode measurements. Print metrics or metricgroups specified in a comma separated list. For a group all metrics from the group are added. The events from the metrics are automatically measured. -See perf list output for the possble metrics and metricgroups. +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 top down level 1 metrics if 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 @@ -317,6 +478,11 @@ if the workload is actually bound by the CPU and not by something else. For best results it is usually a good idea to use it with interval mode like -I 1000, as the bottleneck of workloads can change often. +This enables --metric-only, unless overridden with --no-metric-only. + +The following restrictions only apply to older Intel CPUs and Atom, +on newer CPUs (IceLake and later) TopDown can be collected for any thread: + The top down metrics are collected per core instead of per CPU thread. Per core mode is automatically enabled and -a (global monitoring) is needed, requiring root rights or @@ -328,24 +494,24 @@ echo 0 > /proc/sys/kernel/nmi_watchdog for best results. Otherwise the bottlenecks may be inconsistent on workload with changing phases. -This enables --metric-only, unless overridden with --no-metric-only. - 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. ---no-merge:: -Do not merge results from same PMUs. +--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. -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. +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...'. -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. +Error out if the input is higher than the supported max level. --smi-cost:: Measure SMI cost if msr/aperf/ and msr/smi/ events are supported. @@ -376,10 +542,26 @@ counts for all hardware threads in a core but show the sum counts per hardware thread. This is essentially a replacement for the any bit and convenient for post processing. +--summary:: +Print summary for interval mode (-I). + +--no-csv-summary:: +Don't print 'summary' at the first column for CVS summary output. +This option must be used with -x and --summary. + +This option can be enabled in perf config by setting the variable +'stat.no-csv-summary'. + +$ perf config stat.no-csv-summary=true + +--cputype:: +Only enable events on applying cpu with this type for hybrid platform +(e.g. core or atom)" + EXAMPLES -------- -$ perf stat -- make +$ perf stat \-- make Performance counter stats for 'make': @@ -435,6 +617,29 @@ The fields are in this order: 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. + +- timestamp : optional usec time stamp 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) +- 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) +- runtime : run time of counter +- metric-value : optional metric value +- metric-unit : optional unit of metric + SEE ALSO -------- linkperf:perf-top[1], linkperf:perf-list[1] |