From f5abaa1bfc3dbf26d19d3513f39279ca369f8d65 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 20 Jun 2013 11:44:44 -0400 Subject: tracing: Add DEFINE_EVENT_FN() macro Each TRACE_EVENT() adds several helper functions. If two or more trace events share the same structure and print format, they can also share most of these helper functions and save a lot of space from duplicate code. This is why the DECLARE_EVENT_CLASS() and DEFINE_EVENT() were created. Some events require a trigger to be called at registering and unregistering of the event and to do so they use TRACE_EVENT_FN(). If multiple events require a trigger, they currently have no choice but to use TRACE_EVENT_FN() as there's no DEFINE_EVENT_FN() available. This unfortunately causes a lot of wasted duplicate code created. By adding a DEFINE_EVENT_FN(), these events can still use a DECLARE_EVENT_CLASS() and then define their own triggers. Signed-off-by: Steven Rostedt Link: http://lkml.kernel.org/r/51C3236C.8030508@hds.com Signed-off-by: Seiji Aguchi Signed-off-by: H. Peter Anvin --- include/linux/tracepoint.h | 2 ++ include/trace/define_trace.h | 5 +++++ include/trace/ftrace.h | 4 ++++ 3 files changed, 11 insertions(+) (limited to 'include') diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index f8e084d0fc77..ebeab360d851 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -378,6 +378,8 @@ static inline void tracepoint_synchronize_unregister(void) #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print) #define DEFINE_EVENT(template, name, proto, args) \ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) +#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\ + DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) #define DEFINE_EVENT_CONDITION(template, name, proto, \ diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h index 1905ca8dd399..02e1003568a4 100644 --- a/include/trace/define_trace.h +++ b/include/trace/define_trace.h @@ -44,6 +44,10 @@ #define DEFINE_EVENT(template, name, proto, args) \ DEFINE_TRACE(name) +#undef DEFINE_EVENT_FN +#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg) \ + DEFINE_TRACE_FN(name, reg, unreg) + #undef DEFINE_EVENT_PRINT #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ DEFINE_TRACE(name) @@ -91,6 +95,7 @@ #undef TRACE_EVENT_CONDITION #undef DECLARE_EVENT_CLASS #undef DEFINE_EVENT +#undef DEFINE_EVENT_FN #undef DEFINE_EVENT_PRINT #undef DEFINE_EVENT_CONDITION #undef TRACE_HEADER_MULTI_READ diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 19edd7facaa1..d615f78cc6b6 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -71,6 +71,10 @@ static struct ftrace_event_call __used \ __attribute__((__aligned__(4))) event_##name +#undef DEFINE_EVENT_FN +#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg) \ + DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args)) + #undef DEFINE_EVENT_PRINT #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args)) -- cgit v1.2.3 From cf910e83ae23692fdeefc7e506e504c4c468d38a Mon Sep 17 00:00:00 2001 From: Seiji Aguchi Date: Thu, 20 Jun 2013 11:46:53 -0400 Subject: x86, trace: Add irq vector tracepoints [Purpose of this patch] As Vaibhav explained in the thread below, tracepoints for irq vectors are useful. http://www.spinics.net/lists/mm-commits/msg85707.html The current interrupt traces from irq_handler_entry and irq_handler_exit provide when an interrupt is handled. They provide good data about when the system has switched to kernel space and how it affects the currently running processes. There are some IRQ vectors which trigger the system into kernel space, which are not handled in generic IRQ handlers. Tracing such events gives us the information about IRQ interaction with other system events. The trace also tells where the system is spending its time. We want to know which cores are handling interrupts and how they are affecting other processes in the system. Also, the trace provides information about when the cores are idle and which interrupts are changing that state. On the other hand, my usecase is tracing just local timer event and getting a value of instruction pointer. I suggested to add an argument local timer event to get instruction pointer before. But there is another way to get it with external module like systemtap. So, I don't need to add any argument to irq vector tracepoints now. [Patch Description] Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events. But there is an above use case to trace specific irq_vector rather than tracing all events. In this case, we are concerned about overhead due to unwanted events. So, add following tracepoints instead of introducing irq_vector_entry/exit. so that we can enable them independently. - local_timer_vector - reschedule_vector - call_function_vector - call_function_single_vector - irq_work_entry_vector - error_apic_vector - thermal_apic_vector - threshold_apic_vector - spurious_apic_vector - x86_platform_ipi_vector Also, introduce a logic switching IDT at enabling/disabling time so that a time penalty makes a zero when tracepoints are disabled. Detailed explanations are as follows. - Create trace irq handlers with entering_irq()/exiting_irq(). - Create a new IDT, trace_idt_table, at boot time by adding a logic to _set_gate(). It is just a copy of original idt table. - Register the new handlers for tracpoints to the new IDT by introducing macros to alloc_intr_gate() called at registering time of irq_vector handlers. - Add checking, whether irq vector tracing is on/off, into load_current_idt(). This has to be done below debug checking for these reasons. - Switching to debug IDT may be kicked while tracing is enabled. - On the other hands, switching to trace IDT is kicked only when debugging is disabled. In addition, the new IDT is created only when CONFIG_TRACING is enabled to avoid being used for other purposes. Signed-off-by: Seiji Aguchi Link: http://lkml.kernel.org/r/51C323ED.5050708@hds.com Signed-off-by: H. Peter Anvin Cc: Steven Rostedt --- include/xen/events.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/xen/events.h b/include/xen/events.h index b2b27c6a0f7b..c9ea10ee2273 100644 --- a/include/xen/events.h +++ b/include/xen/events.h @@ -76,6 +76,9 @@ unsigned irq_from_evtchn(unsigned int evtchn); /* Xen HVM evtchn vector callback */ void xen_hvm_callback_vector(void); +#ifdef CONFIG_TRACING +#define trace_xen_hvm_callback_vector xen_hvm_callback_vector +#endif extern int xen_have_vector_callback; int xen_set_callback_via(uint64_t via); void xen_evtchn_do_upcall(struct pt_regs *regs); -- cgit v1.2.3