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torvaldstorvalds
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Merge tag 'trace-tools-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing tools updates from Steven Rostedt: - Introduce enum timerlat_tracing_mode Now that BPF based sampling has been added to timerlat, add an enum to represent which mode timerlat is running in - Add action on timelat threshold feature A new option, --on-threshold, is added, taking an argument that further specifies the action. Actions added in this patch are: - trace[,file=<filename>]: Saves tracefs buffer, optionally taking a filename - signal,num=<sig>,pid=<pid>: Sends signal to process. "parent" might be specified instead of number to send signal to parent process - shell,command=<command>: Execute shell command - Allow resuming tracing in timerlat bpf rtla-timerlat BPF program uses a global variable stored in a .bss section to store whether tracing has been stopped. Map it to allow it to resume tracing after it has been stopped - Add continue action to timerlat Introduce option to resume tracing after a latency threshold overflow. The option is implemented as an action named "continue" - Add action on end feature to timerlat Implement actions on end next to actions on threshold. A new option, --on-end is added, parallel to --on-threshold. Instead of being executed whenever a latency threshold is reached, it is executed at the end of the measurement - Have rtla tests check output with grep Add argument to the check command in the test suite that takes a regular expression that the output of rtla command is checked against. This allows testing for specific information in rtla output in addition to checking the return value - Add tests for timerlat actions - Update the documentation for the new features * tag 'trace-tools-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: rtla/tests: Test timerlat -P option using actions rtla/tests: Add grep checks for base test cases Documentation/rtla: Add actions feature rtla/tests: Limit duration to maximum of 10s rtla/tests: Add tests for actions rtla/tests: Check rtla output with grep rtla/timerlat: Add action on end feature rtla/timerlat: Add continue action rtla/timerlat_bpf: Allow resuming tracing rtla/timerlat: Add action on threshold feature rtla/timerlat: Introduce enum timerlat_tracing_mode
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‎Documentation/tools/rtla/common_timerlat_options.rst

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Set timerlat to run without workload, waiting for the user to dispatch a per-cpu
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task that waits for a new period on the tracing/osnoise/per_cpu/cpu$ID/timerlat_fd.
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See linux/tools/rtla/sample/timerlat_load.py for an example of user-load code.
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**--on-threshold** *action*
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Defines an action to be executed when tracing is stopped on a latency threshold
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specified by **-i/--irq** or **-T/--thread**.
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Multiple --on-threshold actions may be specified, and they will be executed in
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the order they are provided. If any action fails, subsequent actions in the list
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will not be executed.
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Supported actions are:
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- *trace[,file=<filename>]*
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Saves trace output, optionally taking a filename. Alternative to -t/--trace.
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Note that nlike -t/--trace, specifying this multiple times will result in
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the trace being saved multiple times.
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- *signal,num=<sig>,pid=<pid>*
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Sends signal to process. "parent" might be specified in place of pid to target
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the parent process of rtla.
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- *shell,command=<command>*
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Execute shell command.
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- *continue*
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Continue tracing after actions are executed instead of stopping.
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Example:
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$ rtla timerlat -T 20 --on-threshold trace
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--on-threshold shell,command="grep ipi_send timerlat_trace.txt"
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--on-threshold signal,num=2,pid=parent
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This will save a trace with the default filename "timerlat_trace.txt", print its
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lines that contain the text "ipi_send" on standard output, and send signal 2
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(SIGINT) to the parent process.
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Performance Considerations:
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For time-sensitive actions, it is recommended to run **rtla timerlat** with BPF
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support and RT priority. Note that due to implementational limitations, actions
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might be delayed up to one second after tracing is stopped if BPF mode is not
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available or disabled.
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**--on-end** *action*
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Defines an action to be executed at the end of **rtla timerlat** tracing.
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Multiple --on-end actions can be specified, and they will be executed in the order
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they are provided. If any action fails, subsequent actions in the list will not be
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executed.
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See the documentation for **--on-threshold** for the list of supported actions, with
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the exception that *continue* has no effect.
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Example:
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$ rtla timerlat -d 5s --on-end trace
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This runs rtla timerlat with default options and save trace output at the end.

‎tools/tracing/rtla/src/Build

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rtla-y += trace.o
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rtla-y += utils.o
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rtla-y += actions.o
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rtla-y += osnoise.o
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rtla-y += osnoise_top.o
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rtla-y += osnoise_hist.o

‎tools/tracing/rtla/src/actions.c

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// SPDX-License-Identifier: GPL-2.0
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#include <unistd.h>
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#include "actions.h"
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#include "trace.h"
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#include "utils.h"
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/*
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* actions_init - initialize struct actions
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*/
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void
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actions_init(struct actions *self)
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{
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self->size = action_default_size;
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self->list = calloc(self->size, sizeof(struct action));
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self->len = 0;
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self->continue_flag = false;
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memset(&self->present, 0, sizeof(self->present));
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/* This has to be set by the user */
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self->trace_output_inst = NULL;
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}
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/*
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* actions_destroy - destroy struct actions
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*/
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void
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actions_destroy(struct actions *self)
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{
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/* Free any action-specific data */
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for (struct action *action = self->list; action < self->list + self->len; action++) {
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if (action->type == ACTION_SHELL)
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free(action->command);
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if (action->type == ACTION_TRACE_OUTPUT)
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free(action->trace_output);
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}
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/* Free action list */
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free(self->list);
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}
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/*
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* actions_new - Get pointer to new action
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*/
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static struct action *
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actions_new(struct actions *self)
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{
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if (self->size >= self->len) {
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self->size *= 2;
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self->list = realloc(self->list, self->size * sizeof(struct action));
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}
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return &self->list[self->len++];
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}
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/*
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* actions_add_trace_output - add an action to output trace
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*/
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int
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actions_add_trace_output(struct actions *self, const char *trace_output)
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{
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struct action *action = actions_new(self);
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self->present[ACTION_TRACE_OUTPUT] = true;
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action->type = ACTION_TRACE_OUTPUT;
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action->trace_output = calloc(strlen(trace_output) + 1, sizeof(char));
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if (!action->trace_output)
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return -1;
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strcpy(action->trace_output, trace_output);
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return 0;
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}
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/*
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* actions_add_trace_output - add an action to send signal to a process
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*/
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int
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actions_add_signal(struct actions *self, int signal, int pid)
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{
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struct action *action = actions_new(self);
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self->present[ACTION_SIGNAL] = true;
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action->type = ACTION_SIGNAL;
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action->signal = signal;
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action->pid = pid;
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return 0;
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}
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/*
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* actions_add_shell - add an action to execute a shell command
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*/
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int
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actions_add_shell(struct actions *self, const char *command)
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{
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struct action *action = actions_new(self);
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self->present[ACTION_SHELL] = true;
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action->type = ACTION_SHELL;
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action->command = calloc(strlen(command) + 1, sizeof(char));
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if (!action->command)
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return -1;
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strcpy(action->command, command);
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return 0;
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}
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/*
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* actions_add_continue - add an action to resume measurement
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*/
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int
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actions_add_continue(struct actions *self)
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{
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struct action *action = actions_new(self);
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self->present[ACTION_CONTINUE] = true;
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action->type = ACTION_CONTINUE;
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return 0;
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}
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/*
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* actions_parse - add an action based on text specification
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*/
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int
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actions_parse(struct actions *self, const char *trigger)
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{
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enum action_type type = ACTION_NONE;
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char *token;
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char trigger_c[strlen(trigger)];
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/* For ACTION_SIGNAL */
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int signal = 0, pid = 0;
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/* For ACTION_TRACE_OUTPUT */
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char *trace_output;
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strcpy(trigger_c, trigger);
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token = strtok(trigger_c, ",");
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if (strcmp(token, "trace") == 0)
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type = ACTION_TRACE_OUTPUT;
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else if (strcmp(token, "signal") == 0)
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type = ACTION_SIGNAL;
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else if (strcmp(token, "shell") == 0)
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type = ACTION_SHELL;
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else if (strcmp(token, "continue") == 0)
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type = ACTION_CONTINUE;
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else
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/* Invalid trigger type */
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return -1;
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token = strtok(NULL, ",");
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switch (type) {
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case ACTION_TRACE_OUTPUT:
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/* Takes no argument */
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if (token == NULL)
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trace_output = "timerlat_trace.txt";
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else {
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if (strlen(token) > 5 && strncmp(token, "file=", 5) == 0) {
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trace_output = token + 5;
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} else {
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/* Invalid argument */
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return -1;
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}
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token = strtok(NULL, ",");
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if (token != NULL)
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/* Only one argument allowed */
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return -1;
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}
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return actions_add_trace_output(self, trace_output);
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case ACTION_SIGNAL:
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/* Takes two arguments, num (signal) and pid */
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while (token != NULL) {
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if (strlen(token) > 4 && strncmp(token, "num=", 4) == 0) {
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signal = atoi(token + 4);
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} else if (strlen(token) > 4 && strncmp(token, "pid=", 4) == 0) {
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if (strncmp(token + 4, "parent", 7) == 0)
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pid = -1;
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else
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pid = atoi(token + 4);
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} else {
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/* Invalid argument */
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return -1;
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}
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token = strtok(NULL, ",");
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}
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if (!signal || !pid)
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/* Missing argument */
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return -1;
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return actions_add_signal(self, signal, pid);
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case ACTION_SHELL:
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if (token == NULL)
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return -1;
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if (strlen(token) > 8 && strncmp(token, "command=", 8) == 0)
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return actions_add_shell(self, token + 8);
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return -1;
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case ACTION_CONTINUE:
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/* Takes no argument */
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if (token != NULL)
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return -1;
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return actions_add_continue(self);
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default:
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return -1;
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}
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}
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/*
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* actions_perform - perform all actions
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*/
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int
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actions_perform(struct actions *self)
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{
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int pid, retval;
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const struct action *action;
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for (action = self->list; action < self->list + self->len; action++) {
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switch (action->type) {
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case ACTION_TRACE_OUTPUT:
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retval = save_trace_to_file(self->trace_output_inst, action->trace_output);
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if (retval) {
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err_msg("Error saving trace\n");
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return retval;
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}
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break;
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case ACTION_SIGNAL:
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if (action->pid == -1)
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pid = getppid();
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else
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pid = action->pid;
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retval = kill(pid, action->signal);
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if (retval) {
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err_msg("Error sending signal\n");
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return retval;
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}
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break;
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case ACTION_SHELL:
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retval = system(action->command);
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if (retval)
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return retval;
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break;
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case ACTION_CONTINUE:
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self->continue_flag = true;
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return 0;
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default:
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break;
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}
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}
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return 0;
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}

‎tools/tracing/rtla/src/actions.h

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/* SPDX-License-Identifier: GPL-2.0 */
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#include <tracefs.h>
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#include <stdbool.h>
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enum action_type {
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ACTION_NONE = 0,
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ACTION_TRACE_OUTPUT,
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ACTION_SIGNAL,
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ACTION_SHELL,
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ACTION_CONTINUE,
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ACTION_FIELD_N
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};
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struct action {
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enum action_type type;
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union {
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struct {
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/* For ACTION_TRACE_OUTPUT */
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char *trace_output;
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};
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struct {
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/* For ACTION_SIGNAL */
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int signal;
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int pid;
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};
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struct {
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/* For ACTION_SHELL */
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char *command;
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};
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};
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};
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static const int action_default_size = 8;
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struct actions {
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struct action *list;
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int len, size;
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bool present[ACTION_FIELD_N];
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bool continue_flag;
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/* External dependencies */
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struct tracefs_instance *trace_output_inst;
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};
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void actions_init(struct actions *self);
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void actions_destroy(struct actions *self);
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int actions_add_trace_output(struct actions *self, const char *trace_output);
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int actions_add_signal(struct actions *self, int signal, int pid);
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int actions_add_shell(struct actions *self, const char *command);
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int actions_add_continue(struct actions *self);
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int actions_parse(struct actions *self, const char *trigger);
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int actions_perform(struct actions *self);

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