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Commit 4e3c3333 authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

ftrace: fix time offset 



fix time offset calculations and ordering, plus make code more consistent.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 77a2b37d

kernel/trace/trace.c

+55 −20
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ static DEFINE_SPINLOCK(ftrace_max_lock); 
 * structure. (this way the maximum trace is permanently saved,

 * for later retrieval via /debugfs/tracing/latency_trace)

 */

static void notrace

static notrace void

__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)

{

	struct trace_array_cpu *data = tr->data[cpu];
@@ -333,15 +333,16 @@ void unregister_tracer(struct tracer *type) 
	mutex_unlock(&trace_types_lock);

}



void notrace tracing_reset(struct trace_array_cpu *data)

notrace void tracing_reset(struct trace_array_cpu *data)

{

	data->trace_idx = 0;

	data->trace_current = head_page(data);

	data->trace_current_idx = 0;

	data->time_offset = 0;

}



#ifdef CONFIG_FTRACE

static void notrace

static notrace void

function_trace_call(unsigned long ip, unsigned long parent_ip)

{

	struct trace_array *tr = &global_trace;
@@ -398,7 +399,7 @@ static void trace_init_cmdlines(void) 


notrace void trace_stop_cmdline_recording(void);



static void notrace trace_save_cmdline(struct task_struct *tsk)

static notrace void trace_save_cmdline(struct task_struct *tsk)

{

	unsigned map;

	unsigned idx;
@@ -624,6 +625,7 @@ static void *find_next_entry_inc(struct trace_iterator *iter) 
		iter->idx++;

		iter->next_idx[next_cpu]++;

		iter->next_page_idx[next_cpu]++;



		if (iter->next_page_idx[next_cpu] >= ENTRIES_PER_PAGE) {

			struct trace_array_cpu *data = iter->tr->data[next_cpu];
@@ -635,19 +637,21 @@ static void *find_next_entry_inc(struct trace_iterator *iter) 
					data->trace_pages.next;

		}

	}

	iter->prev_ent = iter->ent;

	iter->prev_cpu = iter->cpu;



	iter->ent = next;

	iter->cpu = next_cpu;



	return next ? iter : NULL;

}



static void notrace *

s_next(struct seq_file *m, void *v, loff_t *pos)

static notrace void *s_next(struct seq_file *m, void *v, loff_t *pos)

{

	struct trace_iterator *iter = m->private;

	void *ent;

	void *last_ent = iter->ent;

	int i = (int)*pos;

	void *ent;



	(*pos)++;
@@ -693,6 +697,8 @@ static void *s_start(struct seq_file *m, loff_t *pos) 
		iter->ent = NULL;

		iter->cpu = 0;

		iter->idx = -1;

		iter->prev_ent = NULL;

		iter->prev_cpu = -1;



		for_each_possible_cpu(i) {

			iter->next_idx[i] = 0;
@@ -752,7 +758,7 @@ seq_print_sym_offset(struct seq_file *m, const char *fmt, unsigned long address) 
# define IP_FMT "%016lx"

#endif



static void notrace

static notrace void

seq_print_ip_sym(struct seq_file *m, unsigned long ip, unsigned long sym_flags)

{

	if (!ip) {
@@ -769,7 +775,7 @@ seq_print_ip_sym(struct seq_file *m, unsigned long ip, unsigned long sym_flags) 
		seq_printf(m, " <" IP_FMT ">", ip);

}



static void notrace print_lat_help_header(struct seq_file *m)

static notrace void print_lat_help_header(struct seq_file *m)

{

	seq_puts(m, "#                _------=> CPU#            \n");

	seq_puts(m, "#               / _-----=> irqs-off        \n");
@@ -782,14 +788,14 @@ static void notrace print_lat_help_header(struct seq_file *m) 
	seq_puts(m, "#     \\   /    |||||   \\   |   /           \n");

}



static void notrace print_func_help_header(struct seq_file *m)

static notrace void print_func_help_header(struct seq_file *m)

{

	seq_puts(m, "#           TASK-PID   CPU#    TIMESTAMP  FUNCTION\n");

	seq_puts(m, "#              | |      |          |         |\n");

}





static void notrace

static notrace void

print_trace_header(struct seq_file *m, struct trace_iterator *iter)

{

	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
@@ -858,7 +864,7 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter) 
	seq_puts(m, "\n");

}



static void notrace

static notrace void

lat_print_generic(struct seq_file *m, struct trace_entry *entry, int cpu)

{

	int hardirq, softirq;
@@ -895,7 +901,7 @@ lat_print_generic(struct seq_file *m, struct trace_entry *entry, int cpu) 


unsigned long preempt_mark_thresh = 100;



static void notrace

static notrace void

lat_print_timestamp(struct seq_file *m, unsigned long long abs_usecs,

		    unsigned long rel_usecs)

{
@@ -910,7 +916,7 @@ lat_print_timestamp(struct seq_file *m, unsigned long long abs_usecs, 


static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;



static void notrace

static notrace void

print_lat_fmt(struct seq_file *m, struct trace_iterator *iter,

	      unsigned int trace_idx, int cpu)

{
@@ -966,20 +972,50 @@ print_lat_fmt(struct seq_file *m, struct trace_iterator *iter, 
	}

}



static void notrace

static notrace void sync_time_offset(struct trace_iterator *iter)

{

	struct trace_array_cpu *prev_array, *array;

	struct trace_entry *prev_entry, *entry;

	cycle_t prev_t, t;



	entry = iter->ent;

	prev_entry = iter->prev_ent;

	if (!prev_entry)

		return;



	prev_array = iter->tr->data[iter->prev_cpu];

	array = iter->tr->data[iter->cpu];



	prev_t = prev_entry->t + prev_array->time_offset;

	t = entry->t + array->time_offset;



	/*

	 * If time goes backwards we increase the offset of

	 * the current array, to not have observable time warps.

	 * This will quickly synchronize the time offsets of

	 * multiple CPUs:

	 */

	if (t < prev_t)

		array->time_offset += prev_t - t;

}



static notrace void

print_trace_fmt(struct seq_file *m, struct trace_iterator *iter)

{

	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);

	struct trace_entry *entry = iter->ent;

	struct trace_entry *entry;

	unsigned long usec_rem;

	unsigned long long t;

	unsigned long secs;

	char *comm;

	int S;



	sync_time_offset(iter);

	entry = iter->ent;



	comm = trace_find_cmdline(iter->ent->pid);



	t = ns2usecs(entry->t);

	t = ns2usecs(entry->t + iter->tr->data[iter->cpu]->time_offset);

	usec_rem = do_div(t, 1000000ULL);

	secs = (unsigned long)t;
@@ -1158,7 +1194,7 @@ static int tracing_lt_open(struct inode *inode, struct file *file) 
}





static void notrace *

static notrace void *

t_next(struct seq_file *m, void *v, loff_t *pos)

{

	struct tracer *t = m->private;
@@ -1374,8 +1410,7 @@ tracing_ctrl_read(struct file *filp, char __user *ubuf, 
	int r;



	r = sprintf(buf, "%ld\n", tr->ctrl);

	return simple_read_from_buffer(ubuf, cnt, ppos,

				       buf, r);

	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);

}



static ssize_t

kernel/trace/trace.h

+8 −1
Original line number Diff line number Diff line
@@ -56,6 +56,8 @@ struct trace_array_cpu { 
	void			*trace_current;

	struct list_head	trace_pages;

	atomic_t		disabled;

	cycle_t			time_offset;



	/* these fields get copied into max-trace: */

	unsigned		trace_current_idx;

	unsigned long		trace_idx;
@@ -114,14 +116,19 @@ struct tracer { 
struct trace_iterator {

	struct trace_array	*tr;

	struct tracer		*trace;



	struct trace_entry	*ent;

	int			cpu;



	struct trace_entry	*prev_ent;

	int			prev_cpu;



	unsigned long		iter_flags;

	loff_t			pos;

	unsigned long		next_idx[NR_CPUS];

	struct list_head	*next_page[NR_CPUS];

	unsigned		next_page_idx[NR_CPUS];

	long			idx;

	int			cpu;

};



void notrace tracing_reset(struct trace_array_cpu *data);