| perf-list(1) | |
| ============ | |
| NAME | |
| ---- | |
| perf-list - List all symbolic event types | |
| SYNOPSIS | |
| -------- | |
| [verse] | |
| 'perf list' [--no-desc] [--long-desc] | |
| [hw|sw|cache|tracepoint|pmu|sdt|metric|metricgroup|event_glob] | |
| DESCRIPTION | |
| ----------- | |
| This command displays the symbolic event types which can be selected in the | |
| various perf commands with the -e option. | |
| OPTIONS | |
| ------- | |
| --no-desc:: | |
| Don't print descriptions. | |
| -v:: | |
| --long-desc:: | |
| Print longer event descriptions. | |
| --details:: | |
| Print how named events are resolved internally into perf events, and also | |
| any extra expressions computed by perf stat. | |
| [[EVENT_MODIFIERS]] | |
| EVENT MODIFIERS | |
| --------------- | |
| Events can optionally have a modifier by appending a colon and one or | |
| more modifiers. Modifiers allow the user to restrict the events to be | |
| counted. The following modifiers exist: | |
| u - user-space counting | |
| k - kernel counting | |
| h - hypervisor counting | |
| I - non idle counting | |
| G - guest counting (in KVM guests) | |
| H - host counting (not in KVM guests) | |
| p - precise level | |
| P - use maximum detected precise level | |
| S - read sample value (PERF_SAMPLE_READ) | |
| D - pin the event to the PMU | |
| W - group is weak and will fallback to non-group if not schedulable, | |
| only supported in 'perf stat' for now. | |
| The 'p' modifier can be used for specifying how precise the instruction | |
| address should be. The 'p' modifier can be specified multiple times: | |
| 0 - SAMPLE_IP can have arbitrary skid | |
| 1 - SAMPLE_IP must have constant skid | |
| 2 - SAMPLE_IP requested to have 0 skid | |
| 3 - SAMPLE_IP must have 0 skid, or uses randomization to avoid | |
| sample shadowing effects. | |
| For Intel systems precise event sampling is implemented with PEBS | |
| which supports up to precise-level 2, and precise level 3 for | |
| some special cases | |
| On AMD systems it is implemented using IBS (up to precise-level 2). | |
| The precise modifier works with event types 0x76 (cpu-cycles, CPU | |
| clocks not halted) and 0xC1 (micro-ops retired). Both events map to | |
| IBS execution sampling (IBS op) with the IBS Op Counter Control bit | |
| (IbsOpCntCtl) set respectively (see AMD64 Architecture Programmer’s | |
| Manual Volume 2: System Programming, 13.3 Instruction-Based | |
| Sampling). Examples to use IBS: | |
| perf record -a -e cpu-cycles:p ... # use ibs op counting cycles | |
| perf record -a -e r076:p ... # same as -e cpu-cycles:p | |
| perf record -a -e r0C1:p ... # use ibs op counting micro-ops | |
| RAW HARDWARE EVENT DESCRIPTOR | |
| ----------------------------- | |
| Even when an event is not available in a symbolic form within perf right now, | |
| it can be encoded in a per processor specific way. | |
| For instance For x86 CPUs NNN represents the raw register encoding with the | |
| layout of IA32_PERFEVTSELx MSRs (see [Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide] Figure 30-1 Layout | |
| of IA32_PERFEVTSELx MSRs) or AMD's PerfEvtSeln (see [AMD64 Architecture Programmer’s Manual Volume 2: System Programming], Page 344, | |
| Figure 13-7 Performance Event-Select Register (PerfEvtSeln)). | |
| Note: Only the following bit fields can be set in x86 counter | |
| registers: event, umask, edge, inv, cmask. Esp. guest/host only and | |
| OS/user mode flags must be setup using <<EVENT_MODIFIERS, EVENT | |
| MODIFIERS>>. | |
| Example: | |
| If the Intel docs for a QM720 Core i7 describe an event as: | |
| Event Umask Event Mask | |
| Num. Value Mnemonic Description Comment | |
| A8H 01H LSD.UOPS Counts the number of micro-ops Use cmask=1 and | |
| delivered by loop stream detector invert to count | |
| cycles | |
| raw encoding of 0x1A8 can be used: | |
| perf stat -e r1a8 -a sleep 1 | |
| perf record -e r1a8 ... | |
| You should refer to the processor specific documentation for getting these | |
| details. Some of them are referenced in the SEE ALSO section below. | |
| ARBITRARY PMUS | |
| -------------- | |
| perf also supports an extended syntax for specifying raw parameters | |
| to PMUs. Using this typically requires looking up the specific event | |
| in the CPU vendor specific documentation. | |
| The available PMUs and their raw parameters can be listed with | |
| ls /sys/devices/*/format | |
| For example the raw event "LSD.UOPS" core pmu event above could | |
| be specified as | |
| perf stat -e cpu/event=0xa8,umask=0x1,name=LSD.UOPS_CYCLES,cmask=0x1/ ... | |
| or using extended name syntax | |
| perf stat -e cpu/event=0xa8,umask=0x1,cmask=0x1,name=\'LSD.UOPS_CYCLES:cmask=0x1\'/ ... | |
| PER SOCKET PMUS | |
| --------------- | |
| Some PMUs are not associated with a core, but with a whole CPU socket. | |
| Events on these PMUs generally cannot be sampled, but only counted globally | |
| with perf stat -a. They can be bound to one logical CPU, but will measure | |
| all the CPUs in the same socket. | |
| This example measures memory bandwidth every second | |
| on the first memory controller on socket 0 of a Intel Xeon system | |
| perf stat -C 0 -a uncore_imc_0/cas_count_read/,uncore_imc_0/cas_count_write/ -I 1000 ... | |
| Each memory controller has its own PMU. Measuring the complete system | |
| bandwidth would require specifying all imc PMUs (see perf list output), | |
| and adding the values together. To simplify creation of multiple events, | |
| prefix and glob matching is supported in the PMU name, and the prefix | |
| 'uncore_' is also ignored when performing the match. So the command above | |
| can be expanded to all memory controllers by using the syntaxes: | |
| perf stat -C 0 -a imc/cas_count_read/,imc/cas_count_write/ -I 1000 ... | |
| perf stat -C 0 -a *imc*/cas_count_read/,*imc*/cas_count_write/ -I 1000 ... | |
| This example measures the combined core power every second | |
| perf stat -I 1000 -e power/energy-cores/ -a | |
| ACCESS RESTRICTIONS | |
| ------------------- | |
| For non root users generally only context switched PMU events are available. | |
| This is normally only the events in the cpu PMU, the predefined events | |
| like cycles and instructions and some software events. | |
| Other PMUs and global measurements are normally root only. | |
| Some event qualifiers, such as "any", are also root only. | |
| This can be overriden by setting the kernel.perf_event_paranoid | |
| sysctl to -1, which allows non root to use these events. | |
| For accessing trace point events perf needs to have read access to | |
| /sys/kernel/debug/tracing, even when perf_event_paranoid is in a relaxed | |
| setting. | |
| TRACING | |
| ------- | |
| Some PMUs control advanced hardware tracing capabilities, such as Intel PT, | |
| that allows low overhead execution tracing. These are described in a separate | |
| intel-pt.txt document. | |
| PARAMETERIZED EVENTS | |
| -------------------- | |
| Some pmu events listed by 'perf-list' will be displayed with '?' in them. For | |
| example: | |
| hv_gpci/dtbp_ptitc,phys_processor_idx=?/ | |
| This means that when provided as an event, a value for '?' must | |
| also be supplied. For example: | |
| perf stat -C 0 -e 'hv_gpci/dtbp_ptitc,phys_processor_idx=0x2/' ... | |
| EVENT GROUPS | |
| ------------ | |
| Perf supports time based multiplexing of events, when the number of events | |
| active exceeds the number of hardware performance counters. Multiplexing | |
| can cause measurement errors when the workload changes its execution | |
| profile. | |
| When metrics are computed using formulas from event counts, it is useful to | |
| ensure some events are always measured together as a group to minimize multiplexing | |
| errors. Event groups can be specified using { }. | |
| perf stat -e '{instructions,cycles}' ... | |
| The number of available performance counters depend on the CPU. A group | |
| cannot contain more events than available counters. | |
| For example Intel Core CPUs typically have four generic performance counters | |
| for the core, plus three fixed counters for instructions, cycles and | |
| ref-cycles. Some special events have restrictions on which counter they | |
| can schedule, and may not support multiple instances in a single group. | |
| When too many events are specified in the group some of them will not | |
| be measured. | |
| Globally pinned events can limit the number of counters available for | |
| other groups. On x86 systems, the NMI watchdog pins a counter by default. | |
| The nmi watchdog can be disabled as root with | |
| echo 0 > /proc/sys/kernel/nmi_watchdog | |
| Events from multiple different PMUs cannot be mixed in a group, with | |
| some exceptions for software events. | |
| LEADER SAMPLING | |
| --------------- | |
| perf also supports group leader sampling using the :S specifier. | |
| perf record -e '{cycles,instructions}:S' ... | |
| perf report --group | |
| Normally all events in a event group sample, but with :S only | |
| the first event (the leader) samples, and it only reads the values of the | |
| other events in the group. | |
| OPTIONS | |
| ------- | |
| Without options all known events will be listed. | |
| To limit the list use: | |
| . 'hw' or 'hardware' to list hardware events such as cache-misses, etc. | |
| . 'sw' or 'software' to list software events such as context switches, etc. | |
| . 'cache' or 'hwcache' to list hardware cache events such as L1-dcache-loads, etc. | |
| . 'tracepoint' to list all tracepoint events, alternatively use | |
| 'subsys_glob:event_glob' to filter by tracepoint subsystems such as sched, | |
| block, etc. | |
| . 'pmu' to print the kernel supplied PMU events. | |
| . 'sdt' to list all Statically Defined Tracepoint events. | |
| . 'metric' to list metrics | |
| . 'metricgroup' to list metricgroups with metrics. | |
| . If none of the above is matched, it will apply the supplied glob to all | |
| events, printing the ones that match. | |
| . As a last resort, it will do a substring search in all event names. | |
| One or more types can be used at the same time, listing the events for the | |
| types specified. | |
| Support raw format: | |
| . '--raw-dump', shows the raw-dump of all the events. | |
| . '--raw-dump [hw|sw|cache|tracepoint|pmu|event_glob]', shows the raw-dump of | |
| a certain kind of events. | |
| SEE ALSO | |
| -------- | |
| linkperf:perf-stat[1], linkperf:perf-top[1], | |
| linkperf:perf-record[1], | |
| http://www.intel.com/sdm/[Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide], | |
| http://support.amd.com/us/Processor_TechDocs/24593_APM_v2.pdf[AMD64 Architecture Programmer’s Manual Volume 2: System Programming] |