summaryrefslogtreecommitdiff
path: root/kernel/trace/events.c
AgeCommit message (Collapse)Author
2009-03-20ftrace: event profile hooksPeter Zijlstra
Impact: new tracing infrastructure feature Provide infrastructure to generate software perf counter events from tracepoints. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090319194233.557364871@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-10tracing: use generic __stringifySteven Rostedt
Impact: clean up This removes the custom made STR(x) macros in the tracer and uses the generic __stringify macro instead. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-28tracing: add raw trace point recording infrastructureSteven Rostedt
Impact: lower overhead tracing The current event tracer can automatically pick up trace points that are registered with the TRACE_FORMAT macro. But it required a printf format string and parsing. Although, this adds the ability to get guaranteed information like task names and such, it took a hit in overhead processing. This processing can add about 500-1000 nanoseconds overhead, but in some cases that too is considered too much and we want to shave off as much from this overhead as possible. Tom Zanussi recently posted tracing patches to lkml that are based on a nice idea about capturing the data via C structs using STRUCT_ENTER, STRUCT_EXIT type of macros. I liked that method very much, but did not like the implementation that required a developer to add data/code in several disjoint locations. This patch extends the event_tracer macros to do a similar "raw C" approach that Tom Zanussi did. But instead of having the developers needing to tweak a bunch of code all over the place, they can do it all in one macro - preferably placed near the code that it is tracing. That makes it much more likely that tracepoints will be maintained on an ongoing basis by the code they modify. The new macro TRACE_EVENT_FORMAT is created for this approach. (Note, a developer may still utilize the more low level DECLARE_TRACE macros if they don't care about getting their traces automatically in the event tracer.) They can also use the existing TRACE_FORMAT if they don't need to code the tracepoint in C, but just want to use the convenience of printf. So if the developer wants to "hardwire" a tracepoint in the fastest possible way, and wants to acquire their data via a user space utility in a raw binary format, or wants to see it in the trace output but not sacrifice any performance, then they can implement the faster but more complex TRACE_EVENT_FORMAT macro. Here's what usage looks like: TRACE_EVENT_FORMAT(name, TPPROTO(proto), TPARGS(args), TPFMT(fmt, fmt_args), TRACE_STUCT( TRACE_FIELD(type1, item1, assign1) TRACE_FIELD(type2, item2, assign2) [...] ), TPRAWFMT(raw_fmt) ); Note name, proto, args, and fmt, are all identical to what TRACE_FORMAT uses. name: is the unique identifier of the trace point proto: The proto type that the trace point uses args: the args in the proto type fmt: printf format to use with the event printf tracer fmt_args: the printf argments to match fmt TRACE_STRUCT starts the ability to create a structure. Each item in the structure is defined with a TRACE_FIELD TRACE_FIELD(type, item, assign) type: the C type of item. item: the name of the item in the stucture assign: what to assign the item in the trace point callback raw_fmt is a way to pretty print the struct. It must match the order of the items are added in TRACE_STUCT An example of this would be: TRACE_EVENT_FORMAT(sched_wakeup, TPPROTO(struct rq *rq, struct task_struct *p, int success), TPARGS(rq, p, success), TPFMT("task %s:%d %s", p->comm, p->pid, success?"succeeded":"failed"), TRACE_STRUCT( TRACE_FIELD(pid_t, pid, p->pid) TRACE_FIELD(int, success, success) ), TPRAWFMT("task %d success=%d") ); This creates us a unique struct of: struct { pid_t pid; int success; }; And the way the call back would assign these values would be: entry->pid = p->pid; entry->success = success; The nice part about this is that the creation of the assignent is done via macro magic in the event tracer. Once the TRACE_EVENT_FORMAT is created, the developer will then have a faster method to record into the ring buffer. They do not need to worry about the tracer itself. The developer would only need to touch the files in include/trace/*.h Again, I would like to give special thanks to Tom Zanussi for this nice idea. Idea-from: Tom Zanussi <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-28tracing: add subsystem level to trace eventsSteven Rostedt
If a trace point header defines TRACE_SYSTEM, then it will add the following trace points into that event system. If include/trace/irq_event_types.h has: #define TRACE_SYSTEM irq at the top and #undef TRACE_SYSTEM at the bottom, then a directory "irq" will be created in the /debug/tracing/events directory. Inside that directory will contain the two trace points that are defined in include/trace/irq_event_types.h. Only adding the above to irq and not to sched, we get: # ls /debug/tracing/events/ irq sched_process_exit sched_signal_send sched_wakeup_new sched_kthread_stop sched_process_fork sched_switch sched_kthread_stop_ret sched_process_free sched_wait_task sched_migrate_task sched_process_wait sched_wakeup # ls /debug/tracing/events/irq irq_handler_entry irq_handler_exit If we add #define TRACE_SYSTEM sched to the trace/sched_event_types.h then the rest of the trace events will be put in a sched directory within the events directory. I've been playing with this idea of the subsystem for a while, but recently Tom Zanussi posted some patches to lkml that included this method. Tom's approach was clean and got me to finally put some effort to clean up the event trace points. Thanks to Tom Zanussi for demonstrating how nice the subsystem method is. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-28tracing: move trace point formats to files in include/trace directorySteven Rostedt
Impact: clean up To further facilitate the ease of adding trace points for developers, this patch creates include/trace/trace_events.h and include/trace/trace_event_types.h. The former file will hold the trace/<type>.h files and the latter will hold the trace/<type>_event_types.h files. To create new tracepoints and to have them automatically appear in the event tracer, a developer makes the trace/<type>.h file which includes <linux/tracepoint.h> and the trace/<type>_event_types.h file. The trace/<type>_event_types.h file will hold the TRACE_FORMAT macros. Then add the trace/<type>.h file to trace/trace_events.h, and add the trace/<type>_event_types.h to the trace_event_types.h file. No need to modify files elsewhere. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-26tracing, genirq: add irq enter and exit trace eventsJason Baron
Impact: add new tracepoints Add them to the generic IRQ code, that way every architecture gets these new tracepoints, not just x86. Using Steve's new 'TRACE_FORMAT', I can get function graph trace as follows using the original two IRQ tracepoints: 3) | handle_IRQ_event() { 3) | /* (irq_handler_entry) irq=28 handler=eth0 */ 3) | e1000_intr_msi() { 3) 2.460 us | __napi_schedule(); 3) 9.416 us | } 3) | /* (irq_handler_exit) irq=28 handler=eth0 return=handled */ 3) + 22.935 us | } Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25tracing: add schedule events to event traceSteven Rostedt
This patch changes the trace/sched.h to use the DECLARE_TRACE_FMT such that they are automatically registered with the event tracer. And it also adds the tracing sched headers to kernel/trace/events.c Signed-off-by: Steven Rostedt <srostedt@redhat.com>