summaryrefslogtreecommitdiffstats
path: root/tools/perf/Documentation/perf-script-perl.txt
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /tools/perf/Documentation/perf-script-perl.txt
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'tools/perf/Documentation/perf-script-perl.txt')
-rw-r--r--tools/perf/Documentation/perf-script-perl.txt216
1 files changed, 216 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-script-perl.txt b/tools/perf/Documentation/perf-script-perl.txt
new file mode 100644
index 000000000..5b479f5e6
--- /dev/null
+++ b/tools/perf/Documentation/perf-script-perl.txt
@@ -0,0 +1,216 @@
+perf-script-perl(1)
+===================
+
+NAME
+----
+perf-script-perl - Process trace data with a Perl script
+
+SYNOPSIS
+--------
+[verse]
+'perf script' [-s [Perl]:script[.pl] ]
+
+DESCRIPTION
+-----------
+
+This perf script option is used to process perf script data using perf's
+built-in Perl interpreter. It reads and processes the input file and
+displays the results of the trace analysis implemented in the given
+Perl script, if any.
+
+STARTER SCRIPTS
+---------------
+
+You can avoid reading the rest of this document by running 'perf script
+-g perl' in the same directory as an existing perf.data trace file.
+That will generate a starter script containing a handler for each of
+the event types in the trace file; it simply prints every available
+field for each event in the trace file.
+
+You can also look at the existing scripts in
+~/libexec/perf-core/scripts/perl for typical examples showing how to
+do basic things like aggregate event data, print results, etc. Also,
+the check-perf-script.pl script, while not interesting for its results,
+attempts to exercise all of the main scripting features.
+
+EVENT HANDLERS
+--------------
+
+When perf script is invoked using a trace script, a user-defined
+'handler function' is called for each event in the trace. If there's
+no handler function defined for a given event type, the event is
+ignored (or passed to a 'trace_unhandled' function, see below) and the
+next event is processed.
+
+Most of the event's field values are passed as arguments to the
+handler function; some of the less common ones aren't - those are
+available as calls back into the perf executable (see below).
+
+As an example, the following perf record command can be used to record
+all sched_wakeup events in the system:
+
+ # perf record -a -e sched:sched_wakeup
+
+Traces meant to be processed using a script should be recorded with
+the above option: -a to enable system-wide collection.
+
+The format file for the sched_wakeup event defines the following fields
+(see /sys/kernel/tracing/events/sched/sched_wakeup/format):
+
+----
+ format:
+ field:unsigned short common_type;
+ field:unsigned char common_flags;
+ field:unsigned char common_preempt_count;
+ field:int common_pid;
+
+ field:char comm[TASK_COMM_LEN];
+ field:pid_t pid;
+ field:int prio;
+ field:int success;
+ field:int target_cpu;
+----
+
+The handler function for this event would be defined as:
+
+----
+sub sched::sched_wakeup
+{
+ my ($event_name, $context, $common_cpu, $common_secs,
+ $common_nsecs, $common_pid, $common_comm,
+ $comm, $pid, $prio, $success, $target_cpu) = @_;
+}
+----
+
+The handler function takes the form subsystem::event_name.
+
+The $common_* arguments in the handler's argument list are the set of
+arguments passed to all event handlers; some of the fields correspond
+to the common_* fields in the format file, but some are synthesized,
+and some of the common_* fields aren't common enough to to be passed
+to every event as arguments but are available as library functions.
+
+Here's a brief description of each of the invariant event args:
+
+ $event_name the name of the event as text
+ $context an opaque 'cookie' used in calls back into perf
+ $common_cpu the cpu the event occurred on
+ $common_secs the secs portion of the event timestamp
+ $common_nsecs the nsecs portion of the event timestamp
+ $common_pid the pid of the current task
+ $common_comm the name of the current process
+
+All of the remaining fields in the event's format file have
+counterparts as handler function arguments of the same name, as can be
+seen in the example above.
+
+The above provides the basics needed to directly access every field of
+every event in a trace, which covers 90% of what you need to know to
+write a useful trace script. The sections below cover the rest.
+
+SCRIPT LAYOUT
+-------------
+
+Every perf script Perl script should start by setting up a Perl module
+search path and 'use'ing a few support modules (see module
+descriptions below):
+
+----
+ use lib "$ENV{'PERF_EXEC_PATH'}/scripts/perl/Perf-Trace-Util/lib";
+ use lib "./Perf-Trace-Util/lib";
+ use Perf::Trace::Core;
+ use Perf::Trace::Context;
+ use Perf::Trace::Util;
+----
+
+The rest of the script can contain handler functions and support
+functions in any order.
+
+Aside from the event handler functions discussed above, every script
+can implement a set of optional functions:
+
+*trace_begin*, if defined, is called before any event is processed and
+gives scripts a chance to do setup tasks:
+
+----
+ sub trace_begin
+ {
+ }
+----
+
+*trace_end*, if defined, is called after all events have been
+ processed and gives scripts a chance to do end-of-script tasks, such
+ as display results:
+
+----
+sub trace_end
+{
+}
+----
+
+*trace_unhandled*, if defined, is called after for any event that
+ doesn't have a handler explicitly defined for it. The standard set
+ of common arguments are passed into it:
+
+----
+sub trace_unhandled
+{
+ my ($event_name, $context, $common_cpu, $common_secs,
+ $common_nsecs, $common_pid, $common_comm) = @_;
+}
+----
+
+The remaining sections provide descriptions of each of the available
+built-in perf script Perl modules and their associated functions.
+
+AVAILABLE MODULES AND FUNCTIONS
+-------------------------------
+
+The following sections describe the functions and variables available
+via the various Perf::Trace::* Perl modules. To use the functions and
+variables from the given module, add the corresponding 'use
+Perf::Trace::XXX' line to your perf script script.
+
+Perf::Trace::Core Module
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+These functions provide some essential functions to user scripts.
+
+The *flag_str* and *symbol_str* functions provide human-readable
+strings for flag and symbolic fields. These correspond to the strings
+and values parsed from the 'print fmt' fields of the event format
+files:
+
+ flag_str($event_name, $field_name, $field_value) - returns the string representation corresponding to $field_value for the flag field $field_name of event $event_name
+ symbol_str($event_name, $field_name, $field_value) - returns the string representation corresponding to $field_value for the symbolic field $field_name of event $event_name
+
+Perf::Trace::Context Module
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Some of the 'common' fields in the event format file aren't all that
+common, but need to be made accessible to user scripts nonetheless.
+
+Perf::Trace::Context defines a set of functions that can be used to
+access this data in the context of the current event. Each of these
+functions expects a $context variable, which is the same as the
+$context variable passed into every event handler as the second
+argument.
+
+ common_pc($context) - returns common_preempt count for the current event
+ common_flags($context) - returns common_flags for the current event
+ common_lock_depth($context) - returns common_lock_depth for the current event
+
+Perf::Trace::Util Module
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Various utility functions for use with perf script:
+
+ nsecs($secs, $nsecs) - returns total nsecs given secs/nsecs pair
+ nsecs_secs($nsecs) - returns whole secs portion given nsecs
+ nsecs_nsecs($nsecs) - returns nsecs remainder given nsecs
+ nsecs_str($nsecs) - returns printable string in the form secs.nsecs
+ avg($total, $n) - returns average given a sum and a total number of values
+
+SEE ALSO
+--------
+linkperf:perf-script[1]