ftrace: add sysprof plugin

very first baby version.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/trace/Kconfig

@@ -75,6 +75,14 @@ config PREEMPT_TRACER
 	  enabled. This option and the irqs-off timing option can be
 	  used together or separately.)
 
+config SYSPROF_TRACER
+	bool "Sysprof Tracer"
+	depends on DEBUG_KERNEL
+	select TRACING
+	help
+	  This tracer provides the trace needed by the 'Sysprof' userspace
+	  tool.
+
 config SCHED_TRACER
 	bool "Scheduling Latency Tracer"
 	depends on HAVE_FTRACE

kernel/trace/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_FTRACE) += libftrace.o
 
 obj-$(CONFIG_TRACING) += trace.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
+obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o
 obj-$(CONFIG_FTRACE) += trace_functions.o
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o

kernel/trace/trace_sysprof.c

+/*
+ * trace stack traces
+ *
+ * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/marker.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static struct trace_array	*ctx_trace;
+static int __read_mostly	tracer_enabled;
+
+static notrace void stack_reset(struct trace_array *tr)
+{
+	int cpu;
+
+	tr->time_start = ftrace_now(tr->cpu);
+
+	for_each_online_cpu(cpu)
+		tracing_reset(tr->data[cpu]);
+}
+
+static notrace void start_stack_trace(struct trace_array *tr)
+{
+	stack_reset(tr);
+	tracer_enabled = 1;
+}
+
+static notrace void stop_stack_trace(struct trace_array *tr)
+{
+	tracer_enabled = 0;
+}
+
+static notrace void stack_trace_init(struct trace_array *tr)
+{
+	ctx_trace = tr;
+
+	if (tr->ctrl)
+		start_stack_trace(tr);
+}
+
+static notrace void stack_trace_reset(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		stop_stack_trace(tr);
+}
+
+static void stack_trace_ctrl_update(struct trace_array *tr)
+{
+	/* When starting a new trace, reset the buffers */
+	if (tr->ctrl)
+		start_stack_trace(tr);
+	else
+		stop_stack_trace(tr);
+}
+
+static struct tracer stack_trace __read_mostly =
+{
+	.name		= "sysprof",
+	.init		= stack_trace_init,
+	.reset		= stack_trace_reset,
+	.ctrl_update	= stack_trace_ctrl_update,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_stack,
+#endif
+};
+
+__init static int init_stack_trace(void)
+{
+	return register_tracer(&stack_trace);
+}
+device_initcall(init_stack_trace);