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Commit 30dbb20e authored by Américo Wang's avatar Américo Wang Committed by Frederic Weisbecker
Browse files

tracing: Remove boot tracer 



The boot tracer is useless. It simply logs the initcalls
but in fact these initcalls are also logged through printk
while using the initcall_debug kernel parameter.

Nobody seem to be using it so far. Then just remove it.

Signed-off-by: default avatarWANG Cong <xiyou.wangcong@gmail.com>
Cc: Chase Douglas <chase.douglas@canonical.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <20100526105753.GA5677@cr0.nay.redhat.com>
[ remove the hooks in main.c, and the headers ]
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent b0f82b81

include/trace/boot.h

deleted100644 → 0
+0 −60
Original line number Diff line number Diff line 
#ifndef _LINUX_TRACE_BOOT_H

#define _LINUX_TRACE_BOOT_H



#include <linux/module.h>

#include <linux/kallsyms.h>

#include <linux/init.h>



/*

 * Structure which defines the trace of an initcall

 * while it is called.

 * You don't have to fill the func field since it is

 * only used internally by the tracer.

 */

struct boot_trace_call {

	pid_t			caller;

	char			func[KSYM_SYMBOL_LEN];

};



/*

 * Structure which defines the trace of an initcall

 * while it returns.

 */

struct boot_trace_ret {

	char			func[KSYM_SYMBOL_LEN];

	int				result;

	unsigned long long	duration;		/* nsecs */

};



#ifdef CONFIG_BOOT_TRACER

/* Append the traces on the ring-buffer */

extern void trace_boot_call(struct boot_trace_call *bt, initcall_t fn);

extern void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn);



/* Tells the tracer that smp_pre_initcall is finished.

 * So we can start the tracing

 */

extern void start_boot_trace(void);



/* Resume the tracing of other necessary events

 * such as sched switches

 */

extern void enable_boot_trace(void);



/* Suspend this tracing. Actually, only sched_switches tracing have

 * to be suspended. Initcalls doesn't need it.)

 */

extern void disable_boot_trace(void);

#else

static inline

void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) { }



static inline

void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn) { }



static inline void start_boot_trace(void) { }

static inline void enable_boot_trace(void) { }

static inline void disable_boot_trace(void) { }

#endif /* CONFIG_BOOT_TRACER */



#endif /* __LINUX_TRACE_BOOT_H */

init/main.c

+10 −17
Original line number Diff line number Diff line
@@ -70,7 +70,6 @@ 
#include <linux/sfi.h>

#include <linux/shmem_fs.h>

#include <linux/slab.h>

#include <trace/boot.h>



#include <asm/io.h>

#include <asm/bugs.h>
@@ -715,38 +714,33 @@ int initcall_debug; 
core_param(initcall_debug, initcall_debug, bool, 0644);



static char msgbuf[64];

static struct boot_trace_call call;

static struct boot_trace_ret ret;



int do_one_initcall(initcall_t fn)

{

	int count = preempt_count();

	ktime_t calltime, delta, rettime;

	unsigned long long duration;

	int ret;



	if (initcall_debug) {

		call.caller = task_pid_nr(current);

		printk("calling  %pF @ %i\n", fn, call.caller);

		printk("calling  %pF @ %i\n", fn, task_pid_nr(current));

		calltime = ktime_get();

		trace_boot_call(&call, fn);

		enable_boot_trace();

	}



	ret.result = fn();

	ret = fn();



	if (initcall_debug) {

		disable_boot_trace();

		rettime = ktime_get();

		delta = ktime_sub(rettime, calltime);

		ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;

		trace_boot_ret(&ret, fn);

		printk("initcall %pF returned %d after %Ld usecs\n", fn,

			ret.result, ret.duration);

		duration = (unsigned long long) ktime_to_ns(delta) >> 10;

		printk("initcall %pF returned %d after %lld usecs\n", fn,

			ret, duration);

	}



	msgbuf[0] = 0;



	if (ret.result && ret.result != -ENODEV && initcall_debug)

		sprintf(msgbuf, "error code %d ", ret.result);

	if (ret && ret != -ENODEV && initcall_debug)

		sprintf(msgbuf, "error code %d ", ret);



	if (preempt_count() != count) {

		strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
@@ -760,7 +754,7 @@ int do_one_initcall(initcall_t fn) 
		printk("initcall %pF returned with %s\n", fn, msgbuf);

	}



	return ret.result;

	return ret;

}
@@ -880,7 +874,6 @@ static int __init kernel_init(void * unused) 
	smp_prepare_cpus(setup_max_cpus);



	do_pre_smp_initcalls();

	start_boot_trace();



	smp_init();

	sched_init_smp();

kernel/trace/Kconfig

+0 −17
Original line number Diff line number Diff line
@@ -229,23 +229,6 @@ config FTRACE_SYSCALLS 
	help

	  Basic tracer to catch the syscall entry and exit events.



config BOOT_TRACER

	bool "Trace boot initcalls"

	select GENERIC_TRACER

	select CONTEXT_SWITCH_TRACER

	help

	  This tracer helps developers to optimize boot times: it records

	  the timings of the initcalls and traces key events and the identity

	  of tasks that can cause boot delays, such as context-switches.



	  Its aim is to be parsed by the scripts/bootgraph.pl tool to

	  produce pretty graphics about boot inefficiencies, giving a visual

	  representation of the delays during initcalls - but the raw

	  /debug/tracing/trace text output is readable too.



	  You must pass in initcall_debug and ftrace=initcall to the kernel

	  command line to enable this on bootup.



config TRACE_BRANCH_PROFILING

	bool

	select GENERIC_TRACER

kernel/trace/Makefile

+0 −1
Original line number Diff line number Diff line
@@ -38,7 +38,6 @@ obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o 
obj-$(CONFIG_NOP_TRACER) += trace_nop.o

obj-$(CONFIG_STACK_TRACER) += trace_stack.o

obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o

obj-$(CONFIG_BOOT_TRACER) += trace_boot.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o

obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o

obj-$(CONFIG_KMEMTRACE) += kmemtrace.o

kernel/trace/trace.c

+0 −3
Original line number Diff line number Diff line
@@ -4603,9 +4603,6 @@ __init static int tracer_alloc_buffers(void) 


	register_tracer(&nop_trace);

	current_trace = &nop_trace;

#ifdef CONFIG_BOOT_TRACER

	register_tracer(&boot_tracer);

#endif

	/* All seems OK, enable tracing */

	tracing_disabled = 0;