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Commit 0012693a authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

tracing/function-graph-tracer: use the more lightweight local clock 



Impact: decrease hangs risks with the graph tracer on slow systems

Since the function graph tracer can spend too much time on timer
interrupts, it's better now to use the more lightweight local
clock. Anyway, the function graph traces are more reliable on a
per cpu trace.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <49af243d.06e9300a.53ad.ffff840c@mx.google.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c4ef144a

arch/x86/kernel/ftrace.c

+1 −1
Original line number Diff line number Diff line
@@ -436,7 +436,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) 
		return;

	}



	calltime = cpu_clock(raw_smp_processor_id());

	calltime = trace_clock_local();



	if (ftrace_push_return_trace(old, calltime,

				self_addr, &trace.depth) == -EBUSY) {

include/linux/ftrace.h

+7 −6
Original line number Diff line number Diff line 
#ifndef _LINUX_FTRACE_H

#define _LINUX_FTRACE_H



#include <linux/linkage.h>

#include <linux/fs.h>

#include <linux/ktime.h>

#include <linux/init.h>

#include <linux/types.h>

#include <linux/module.h>

#include <linux/trace_clock.h>

#include <linux/kallsyms.h>

#include <linux/linkage.h>

#include <linux/bitops.h>

#include <linux/module.h>

#include <linux/ktime.h>

#include <linux/sched.h>

#include <linux/types.h>

#include <linux/init.h>

#include <linux/fs.h>



#include <asm/ftrace.h>

kernel/trace/trace_functions_graph.c

+1 −1
Original line number Diff line number Diff line
@@ -112,7 +112,7 @@ unsigned long ftrace_return_to_handler(void) 
	unsigned long ret;



	ftrace_pop_return_trace(&trace, &ret);

	trace.rettime = cpu_clock(raw_smp_processor_id());

	trace.rettime = trace_clock_local();

	ftrace_graph_return(&trace);



	if (unlikely(!ret)) {