diff options
Diffstat (limited to 'samples/trace_events')
| -rw-r--r-- | samples/trace_events/Makefile | 2 | ||||
| -rw-r--r-- | samples/trace_events/trace_custom_sched.c | 60 | ||||
| -rw-r--r-- | samples/trace_events/trace_custom_sched.h | 96 |
3 files changed, 158 insertions, 0 deletions
diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile index b78344e7bbed..b3808bb4cf8b 100644 --- a/samples/trace_events/Makefile +++ b/samples/trace_events/Makefile @@ -11,5 +11,7 @@ # Here trace-events-sample.c does the CREATE_TRACE_POINTS. # CFLAGS_trace-events-sample.o := -I$(src) +CFLAGS_trace_custom_sched.o := -I$(src) obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o +obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_custom_sched.o diff --git a/samples/trace_events/trace_custom_sched.c b/samples/trace_events/trace_custom_sched.c new file mode 100644 index 000000000000..b99d9ab7db85 --- /dev/null +++ b/samples/trace_events/trace_custom_sched.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * event tracer + * + * Copyright (C) 2022 Google Inc, Steven Rostedt <rostedt@goodmis.org> + */ + +#define pr_fmt(fmt) fmt + +#include <linux/trace_events.h> +#include <linux/version.h> +#include <linux/module.h> +#include <linux/sched.h> + +/* + * Must include the event header that the custom event will attach to, + * from the C file, and not in the custom header file. + */ +#include <trace/events/sched.h> + +/* Declare CREATE_CUSTOM_TRACE_EVENTS before including custom header */ +#define CREATE_CUSTOM_TRACE_EVENTS + +#include "trace_custom_sched.h" + +/* + * As the trace events are not exported to modules, the use of + * for_each_kernel_tracepoint() is needed to find the trace event + * to attach to. The fct() function below, is a callback that + * will be called for every event. + * + * Helper functions are created by the TRACE_CUSTOM_EVENT() macro + * update the event. Those are of the form: + * + * trace_custom_event_<event>_update() + * + * Where <event> is the event to attach. + */ +static void fct(struct tracepoint *tp, void *priv) +{ + trace_custom_event_sched_switch_update(tp); + trace_custom_event_sched_waking_update(tp); +} + +static int __init trace_sched_init(void) +{ + for_each_kernel_tracepoint(fct, NULL); + return 0; +} + +static void __exit trace_sched_exit(void) +{ +} + +module_init(trace_sched_init); +module_exit(trace_sched_exit); + +MODULE_AUTHOR("Steven Rostedt"); +MODULE_DESCRIPTION("Custom scheduling events"); +MODULE_LICENSE("GPL"); diff --git a/samples/trace_events/trace_custom_sched.h b/samples/trace_events/trace_custom_sched.h new file mode 100644 index 000000000000..9fdd8e7c2a45 --- /dev/null +++ b/samples/trace_events/trace_custom_sched.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Like the headers that use TRACE_EVENT(), the TRACE_CUSTOM_EVENT() + * needs a header that allows for multiple inclusions. + * + * Test for a unique name (here we have _TRACE_CUSTOM_SCHED_H), + * also allowing to continue if TRACE_CUSTOM_MULTI_READ is defined. + */ +#if !defined(_TRACE_CUSTOM_SCHED_H) || defined(TRACE_CUSTOM_MULTI_READ) +#define _TRACE_CUSTOM_SCHED_H + +/* Include linux/trace_events.h for initial defines of TRACE_CUSTOM_EVENT() */ +#include <linux/trace_events.h> + +/* + * TRACE_CUSTOM_EVENT() is just like TRACE_EVENT(). The first parameter + * is the event name of an existing event where the TRACE_EVENT has been included + * in the C file before including this file. + */ +TRACE_CUSTOM_EVENT(sched_switch, + + /* + * The TP_PROTO() and TP_ARGS must match the trace event + * that the custom event is using. + */ + TP_PROTO(bool preempt, + unsigned int prev_state, + struct task_struct *prev, + struct task_struct *next), + + TP_ARGS(preempt, prev_state, prev, next), + + /* + * The next fields are where the customization happens. + * The TP_STRUCT__entry() defines what will be recorded + * in the ring buffer when the custom event triggers. + * + * The rest is just like the TRACE_EVENT() macro except that + * it uses the custom entry. + */ + TP_STRUCT__entry( + __field( unsigned short, prev_prio ) + __field( unsigned short, next_prio ) + __field( pid_t, next_pid ) + ), + + TP_fast_assign( + __entry->prev_prio = prev->prio; + __entry->next_pid = next->pid; + __entry->next_prio = next->prio; + ), + + TP_printk("prev_prio=%d next_pid=%d next_prio=%d", + __entry->prev_prio, __entry->next_pid, __entry->next_prio) +) + + +TRACE_CUSTOM_EVENT(sched_waking, + + TP_PROTO(struct task_struct *p), + + TP_ARGS(p), + + TP_STRUCT__entry( + __field( pid_t, pid ) + __field( unsigned short, prio ) + ), + + TP_fast_assign( + __entry->pid = p->pid; + __entry->prio = p->prio; + ), + + TP_printk("pid=%d prio=%d", __entry->pid, __entry->prio) +) +#endif +/* + * Just like the headers that create TRACE_EVENTs, the below must + * be outside the protection of the above #if block. + */ + +/* + * It is required that the Makefile includes: + * CFLAGS_<c_file>.o := -I$(src) + */ +#undef TRACE_INCLUDE_PATH +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_PATH . + +/* + * It is requred that the TRACE_INCLUDE_FILE be the same + * as this file without the ".h". + */ +#define TRACE_INCLUDE_FILE trace_custom_sched +#include <trace/define_custom_trace.h> |