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LIBPFM(3) Linux Programmer's ManualLIBPFM(3)libpfm_perf_event_raw - support for perf_events raw events syntax
#include <perfmon/pfmlib.h>PMU name: perf_rawPMU desc: Raw perf_events event syntax
The library supports a pseudo PMU model to allow raw encodings of PMU events for the Linux perf_events kernel interface. With this PMU, it is possible to provide the raw hexadecimal encoding of any hardware event for any PMU models. The raw encoding is passed as is to the kernel. All events are encoded asPERF_TYPE_RAW. As such, perf_events generic events, such as cycles, instructions, cannot be encoded by this PMU. The syntax is very simple: rX. X is the hexadecimal 64-bit value for the event. It may include event filters on some PMU models. The hexadecimal number is passed without the 0x prefix, e.g., r01c4. The library's standard perf_events attributes are supported by this PMU model. They are separated with colons as is customary with the library.
The following modifiers are supported by this PMU model:uMeasure at user level which includes privilege levels 1, 2, 3. This corresponds toPFM_PLM3. This is a boolean modifier.kMeasure at kernel level which includes privilege level 0. This corresponds toPFM_PLM0. This is a boolean modifier.hMeasure at the hypervisor level. This corresponds toPFM_PLMH. This is a boolean modifiermgMeasure guest execution only. This is a boolean modifiermhMeasure host execution only. This is a boolean modifierperiodSpecify the the sampling period value. Value can be expressed in decimal or hexadecimal. Value is 64-bit wide. This option is mutually exclusive withfreq. The period is expressed in the unit of the event. There is no default value.freqSpecify the the sampling frequency value. Value can be expressed in decimal or hexadecimal. Value is 64-bit wide. This options is mutually exclusive withperiod. The value is expressed in Hertz. For instance, freq=100, means that the event should be sampled 100 times per second on average. There is no default value.exclThe associated event is the only event measured on the PMU. This applies only to hardware events. This attribute requires admin privileges. Default is off.precise Enables precise sampling mode. This option is only valid when sampling on events. The options takes an integer argument. It can have the following values: 1=enable precise sampling, 2=enable precise sampling and eliminate skid, 3=enable precise sampling, eliminate skid and bias. Not all events necessarily support precise mode at all levels, this is dependent on the underlying PMU. Eliminating skid is a best effort feature. It may not work for all samples. This option is mutually exclusive withhw_smpl. This options implies using the hardware assist sampling mechanism.hw_smpl Enables hardware assist sampling. This is a boolean option. It is false by default. On some processors, it is possible to have the hardware record samples in a buffer and then notify the kernel when it is full. Such feature may not be available for all events. Using a hardware buffer does not necessarily eliminate skid and bias, it usually lowers the overhead of interrupt-based sampling by amortizing the interrupt over multiple samples. This option is usually implicit with precise sampling events.cpuThis integer option is used with system-wide events, i.e., events attached to a CPU instead of a thread. The value designate the CPU to attach the event to. It is up to the caller of the library to use the cpu field in the library event encoding argument to create the event. No verification on the validity of the CPU number is made by the library. Default value is -1 for this field.pinnedThis boolean option is used with system-wide events, i.e., events attached to a CPU instead of a thread. If set, then the event is marked as pinned. That means it needs to remain on the counters at all time, i.e., it cannot be multiplexed. There can only be as many pinned events as there are counters, yet the library does not check for that, the perf_event subsystem does. The default value for this field is false, i.e., the event is not pinned.
Stephane Eranian <eranian@gmail.com>
This page is part of theperfmon2 (a performance monitoring library) project. Information about the project can be found at ⟨http://perfmon2.sourceforge.net/⟩. If you have a bug report for this manual page, send it to perfmon2-devel@lists.sourceforge.net. This page was obtained from the project's upstream Git repository ⟨git://git.code.sf.net/p/perfmon2/libpfm4 perfmon2-libpfm4⟩ on 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2025-06-29.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.org February, 2014LIBPFM(3)HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |