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Subject[Patch] tracing: remove boot tracer
On Tue, May 25, 2010 at 10:17:43PM +0200, Frederic Weisbecker wrote:
>On Tue, May 25, 2010 at 03:46:08PM -0400, Steven Rostedt wrote:
>> > CONFIG_BOOT_TRACER=y (no performance impact by default)
>>
>> But this tracer is pretty useless. It gives no more information than
>> debug_initcalls.
>
>
>
>Yeah it's pretty useless. And these informations can also be displayed
>through printk on boot so...


Then just remove it.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>

---

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 8b1797c..572992a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -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
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index ffb1a5b..c3aaeba 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -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
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8a76339..687c487 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4602,9 +4602,6 @@ __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;

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
deleted file mode 100644
index c21d5f3..0000000
--- a/kernel/trace/trace_boot.c
+++ /dev/null
@@ -1,185 +0,0 @@
-/*
- * ring buffer based initcalls tracer
- *
- * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
- *
- */
-
-#include <linux/init.h>
-#include <linux/debugfs.h>
-#include <linux/ftrace.h>
-#include <linux/kallsyms.h>
-#include <linux/time.h>
-
-#include "trace.h"
-#include "trace_output.h"
-
-static struct trace_array *boot_trace;
-static bool pre_initcalls_finished;
-
-/* Tells the boot tracer that the pre_smp_initcalls are finished.
- * So we are ready .
- * It doesn't enable sched events tracing however.
- * You have to call enable_boot_trace to do so.
- */
-void start_boot_trace(void)
-{
- pre_initcalls_finished = true;
-}
-
-void enable_boot_trace(void)
-{
- if (boot_trace && pre_initcalls_finished)
- tracing_start_sched_switch_record();
-}
-
-void disable_boot_trace(void)
-{
- if (boot_trace && pre_initcalls_finished)
- tracing_stop_sched_switch_record();
-}
-
-static int boot_trace_init(struct trace_array *tr)
-{
- boot_trace = tr;
-
- if (!tr)
- return 0;
-
- tracing_reset_online_cpus(tr);
-
- tracing_sched_switch_assign_trace(tr);
- return 0;
-}
-
-static enum print_line_t
-initcall_call_print_line(struct trace_iterator *iter)
-{
- struct trace_entry *entry = iter->ent;
- struct trace_seq *s = &iter->seq;
- struct trace_boot_call *field;
- struct boot_trace_call *call;
- u64 ts;
- unsigned long nsec_rem;
- int ret;
-
- trace_assign_type(field, entry);
- call = &field->boot_call;
- ts = iter->ts;
- nsec_rem = do_div(ts, NSEC_PER_SEC);
-
- ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
- (unsigned long)ts, nsec_rem, call->func, call->caller);
-
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- else
- return TRACE_TYPE_HANDLED;
-}
-
-static enum print_line_t
-initcall_ret_print_line(struct trace_iterator *iter)
-{
- struct trace_entry *entry = iter->ent;
- struct trace_seq *s = &iter->seq;
- struct trace_boot_ret *field;
- struct boot_trace_ret *init_ret;
- u64 ts;
- unsigned long nsec_rem;
- int ret;
-
- trace_assign_type(field, entry);
- init_ret = &field->boot_ret;
- ts = iter->ts;
- nsec_rem = do_div(ts, NSEC_PER_SEC);
-
- ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
- "returned %d after %llu msecs\n",
- (unsigned long) ts,
- nsec_rem,
- init_ret->func, init_ret->result, init_ret->duration);
-
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- else
- return TRACE_TYPE_HANDLED;
-}
-
-static enum print_line_t initcall_print_line(struct trace_iterator *iter)
-{
- struct trace_entry *entry = iter->ent;
-
- switch (entry->type) {
- case TRACE_BOOT_CALL:
- return initcall_call_print_line(iter);
- case TRACE_BOOT_RET:
- return initcall_ret_print_line(iter);
- default:
- return TRACE_TYPE_UNHANDLED;
- }
-}
-
-struct tracer boot_tracer __read_mostly =
-{
- .name = "initcall",
- .init = boot_trace_init,
- .reset = tracing_reset_online_cpus,
- .print_line = initcall_print_line,
-};
-
-void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
-{
- struct ftrace_event_call *call = &event_boot_call;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
- struct trace_boot_call *entry;
- struct trace_array *tr = boot_trace;
-
- if (!tr || !pre_initcalls_finished)
- return;
-
- /* Get its name now since this function could
- * disappear because it is in the .init section.
- */
- sprint_symbol(bt->func, (unsigned long)fn);
- preempt_disable();
-
- buffer = tr->buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_CALL,
- sizeof(*entry), 0, 0);
- if (!event)
- goto out;
- entry = ring_buffer_event_data(event);
- entry->boot_call = *bt;
- if (!filter_check_discard(call, entry, buffer, event))
- trace_buffer_unlock_commit(buffer, event, 0, 0);
- out:
- preempt_enable();
-}
-
-void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
-{
- struct ftrace_event_call *call = &event_boot_ret;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
- struct trace_boot_ret *entry;
- struct trace_array *tr = boot_trace;
-
- if (!tr || !pre_initcalls_finished)
- return;
-
- sprint_symbol(bt->func, (unsigned long)fn);
- preempt_disable();
-
- buffer = tr->buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_RET,
- sizeof(*entry), 0, 0);
- if (!event)
- goto out;
- entry = ring_buffer_event_data(event);
- entry->boot_ret = *bt;
- if (!filter_check_discard(call, entry, buffer, event))
- trace_buffer_unlock_commit(buffer, event, 0, 0);
- out:
- preempt_enable();
-}

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