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trace: better manage the context info for events

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Impact: make trace_event more convenient for tracers

All tracers (for the moment) that use the struct trace_event want to
have the context info printed before their own output: the pid/cmdline,
cpu, and timestamp.

But some other tracers that want to implement their trace_event
callbacks will not necessary need these information or they may want to
format them as they want.

This patch adds a new default-enabled trace option:
TRACE_ITER_CONTEXT_INFO When disabled through:

echo nocontext-info > /debugfs/tracing/trace_options

The pid, cpu and timestamps headers will not be printed.

IE with the sched_switch tracer with context-info (default):

     bash-2935 [001] 100.356561: 2935:120:S ==> [001]  0:140:R <idle>
   <idle>-0    [000] 100.412804:    0:140:R   + [000] 11:115:S events/0
   <idle>-0    [000] 100.412816:    0:140:R ==> [000] 11:115:R events/0
 events/0-11   [000] 100.412829:   11:115:S ==> [000]  0:140:R <idle>

Without context-info:

 2935:120:S ==> [001]  0:140:R <idle>
    0:140:R   + [000] 11:115:S events/0
    0:140:R ==> [000] 11:115:R events/0
   11:115:S ==> [000]  0:140:R <idle>

A tracer can disable it at runtime by clearing the bit
TRACE_ITER_CONTEXT_INFO in trace_flags.

The print routines were renamed to trace_print_context and
trace_print_lat_context, so that they can be used by tracers if they
want to use them for one of the trace_event callbacks.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker
2009-02-02 20:29:21 -02:00
committed by Ingo Molnar
parent dc573f9b20
commit c4a8e8be2d
4 changed files with 151 additions and 115 deletions
Download Patch File Download Diff File Expand all files Collapse all files

107
kernel/trace/trace_output.c
View File

@@ -286,6 +286,113 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
return ret;
}
static void
lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
{
int hardirq, softirq;
char *comm;
comm = trace_find_cmdline(entry->pid);
trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
trace_seq_printf(s, "%3d", cpu);
trace_seq_printf(s, "%c%c",
(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
if (hardirq && softirq) {
trace_seq_putc(s, 'H');
} else {
if (hardirq) {
trace_seq_putc(s, 'h');
} else {
if (softirq)
trace_seq_putc(s, 's');
else
trace_seq_putc(s, '.');
}
}
if (entry->preempt_count)
trace_seq_printf(s, "%x", entry->preempt_count);
else
trace_seq_puts(s, ".");
}
static unsigned long preempt_mark_thresh = 100;
static void
lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
unsigned long rel_usecs)
{
trace_seq_printf(s, " %4lldus", abs_usecs);
if (rel_usecs > preempt_mark_thresh)
trace_seq_puts(s, "!: ");
else if (rel_usecs > 1)
trace_seq_puts(s, "+: ");
else
trace_seq_puts(s, " : ");
}
int trace_print_context(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
char *comm = trace_find_cmdline(entry->pid);
unsigned long long t = ns2usecs(iter->ts);
unsigned long usec_rem = do_div(t, USEC_PER_SEC);
unsigned long secs = (unsigned long)t;
if (!trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid))
goto partial;
if (!trace_seq_printf(s, "[%03d] ", entry->cpu))
goto partial;
if (!trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem))
goto partial;
return 0;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
int trace_print_lat_context(struct trace_iterator *iter)
{
u64 next_ts;
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent,
*next_entry = trace_find_next_entry(iter, NULL,
&next_ts);
unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
unsigned long abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
unsigned long rel_usecs;
if (!next_entry)
next_ts = iter->ts;
rel_usecs = ns2usecs(next_ts - iter->ts);
if (verbose) {
char *comm = trace_find_cmdline(entry->pid);
trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]"
" %ld.%03ldms (+%ld.%03ldms): ",
comm,
entry->pid, entry->cpu, entry->flags,
entry->preempt_count, iter->idx,
ns2usecs(iter->ts),
abs_usecs/1000,
abs_usecs % 1000, rel_usecs/1000,
rel_usecs % 1000);
} else {
lat_print_generic(s, entry, entry->cpu);
lat_print_timestamp(s, abs_usecs, rel_usecs);
}
return 0;
}
static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
static int task_state_char(unsigned long state)