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tracing: Format non-nanosec times from tsc clock without a decimal point. 

With the addition of the "tsc" clock, formatting timestamps to look like
fractional seconds is misleading. Mark clocks as either in nanoseconds or
not, and format non-nanosecond timestamps as decimal integers.

Tested:
$ cd /sys/kernel/debug/tracing/
$ cat trace_clock
[local] global tsc
$ echo sched_switch > set_event
$ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on
$ cat trace
          <idle>-0     [000]  6330.555552: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120
           sleep-29964 [000]  6330.555628: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120
  ...
$ echo 1 > options/latency-format
$ cat trace
  <idle>-0       0 4104553247us+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=29964 next_prio=120
   sleep-29964   0 4104553322us+: sched_switch: prev_comm=bash prev_pid=29964 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120
  ...
$ echo tsc > trace_clock
$ cat trace
$ echo 1 > tracing_on ; sleep 0.0005 ; echo 0 > tracing_on
$ echo 0 > options/latency-format
$ cat trace
          <idle>-0     [000] 16490053398357: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120
           sleep-31128 [000] 16490053588518: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120
  ...
echo 1 > options/latency-format
$ cat trace
  <idle>-0       0 91557653238+: sched_switch: prev_comm=swapper prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=31128 next_prio=120
   sleep-31128   0 91557843399+: sched_switch: prev_comm=bash prev_pid=31128 prev_prio=120 prev_state=S ==> next_comm=swapper next_pid=0 next_prio=120
  ...

v2:
Move arch-specific bits out of generic code.
v4:
Fix x86_32 build due to 64-bit division.

Google-Bug-Id: 6980623
Link: http://lkml.kernel.org/r/1352837903-32191-2-git-send-email-dhsharp@google.com

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: David Sharp <dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
David Sharp 2012-11-13 12:18:22 -08:00 committed by Steven Rostedt
parent 8cbd9cc625
commit 8be0709f10
5 changed files with 72 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/trace_clock.h
View File

@ -9,7 +9,7 @@
extern u64 notrace trace_clock_x86_tsc(void);
# define ARCH_TRACE_CLOCKS \
{ trace_clock_x86_tsc, "x86-tsc" },
{ trace_clock_x86_tsc, "x86-tsc", .in_ns = 0 },
#else /* !CONFIG_X86_TSC */

6
include/linux/ftrace_event.h
View File

@ -86,6 +86,12 @@ struct trace_iterator {
cpumask_var_t started;
};
enum trace_iter_flags {
TRACE_FILE_LAT_FMT = 1,
TRACE_FILE_ANNOTATE = 2,
TRACE_FILE_TIME_IN_NS = 4,
};
struct trace_event;

15
kernel/trace/trace.c
View File

@ -484,10 +484,11 @@ static const char *trace_options[] = {
static struct {
u64 (*func)(void);
const char *name;
int in_ns; /* is this clock in nanoseconds? */
} trace_clocks[] = {
{ trace_clock_local, "local" },
{ trace_clock_global, "global" },
{ trace_clock_counter, "counter" },
{ trace_clock_local, "local", 1 },
{ trace_clock_global, "global", 1 },
{ trace_clock_counter, "counter", 0 },
ARCH_TRACE_CLOCKS
};
@ -2478,6 +2479,10 @@ __tracing_open(struct inode *inode, struct file *file)
if (ring_buffer_overruns(iter->tr->buffer))
iter->iter_flags |= TRACE_FILE_ANNOTATE;
/* Output in nanoseconds only if we are using a clock in nanoseconds. */
if (trace_clocks[trace_clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
/* stop the trace while dumping */
tracing_stop();
@ -3339,6 +3344,10 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
if (trace_flags & TRACE_ITER_LATENCY_FMT)
iter->iter_flags |= TRACE_FILE_LAT_FMT;
/* Output in nanoseconds only if we are using a clock in nanoseconds. */
if (trace_clocks[trace_clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
iter->cpu_file = cpu_file;
iter->tr = &global_trace;
mutex_init(&iter->mutex);

4
kernel/trace/trace.h
View File

@ -406,10 +406,6 @@ void tracing_stop_sched_switch_record(void);
void tracing_start_sched_switch_record(void);
int register_tracer(struct tracer *type);
int is_tracing_stopped(void);
enum trace_file_type {
TRACE_FILE_LAT_FMT = 1,
TRACE_FILE_ANNOTATE = 2,
};
extern cpumask_var_t __read_mostly tracing_buffer_mask;

78
kernel/trace/trace_output.c
View File

@ -610,24 +610,54 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
return trace_print_lat_fmt(s, entry);
}
static unsigned long preempt_mark_thresh = 100;
static unsigned long preempt_mark_thresh_us = 100;
static int
lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
unsigned long rel_usecs)
lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
{
return trace_seq_printf(s, " %4lldus%c: ", abs_usecs,
rel_usecs > preempt_mark_thresh ? '!' :
rel_usecs > 1 ? '+' : ' ');
unsigned long verbose = trace_flags & TRACE_ITER_VERBOSE;
unsigned long in_ns = iter->iter_flags & TRACE_FILE_TIME_IN_NS;
unsigned long long abs_ts = iter->ts - iter->tr->time_start;
unsigned long long rel_ts = next_ts - iter->ts;
struct trace_seq *s = &iter->seq;
if (in_ns) {
abs_ts = ns2usecs(abs_ts);
rel_ts = ns2usecs(rel_ts);
}
if (verbose && in_ns) {
unsigned long abs_usec = do_div(abs_ts, USEC_PER_MSEC);
unsigned long abs_msec = (unsigned long)abs_ts;
unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
unsigned long rel_msec = (unsigned long)rel_ts;
return trace_seq_printf(
s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
ns2usecs(iter->ts),
abs_msec, abs_usec,
rel_msec, rel_usec);
} else if (verbose && !in_ns) {
return trace_seq_printf(
s, "[%016llx] %lld (+%lld): ",
iter->ts, abs_ts, rel_ts);
} else if (!verbose && in_ns) {
return trace_seq_printf(
s, " %4lldus%c: ",
abs_ts,
rel_ts > preempt_mark_thresh_us ? '!' :
rel_ts > 1 ? '+' : ' ');
} else { /* !verbose && !in_ns */
return trace_seq_printf(s, " %4lld: ", abs_ts);
}
}
int trace_print_context(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
unsigned long long t = ns2usecs(iter->ts);
unsigned long usec_rem = do_div(t, USEC_PER_SEC);
unsigned long secs = (unsigned long)t;
unsigned long long t;
unsigned long secs, usec_rem;
char comm[TASK_COMM_LEN];
int ret;
@ -644,8 +674,13 @@ int trace_print_context(struct trace_iterator *iter)
return 0;
}
return trace_seq_printf(s, " %5lu.%06lu: ",
secs, usec_rem);
if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
t = ns2usecs(iter->ts);
usec_rem = do_div(t, USEC_PER_SEC);
secs = (unsigned long)t;
return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
} else
return trace_seq_printf(s, " %12llu: ", iter->ts);
}
int trace_print_lat_context(struct trace_iterator *iter)
@ -659,36 +694,29 @@ int trace_print_lat_context(struct trace_iterator *iter)
*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;
/* Restore the original ent_size */
iter->ent_size = ent_size;
if (!next_entry)
next_ts = iter->ts;
rel_usecs = ns2usecs(next_ts - iter->ts);
if (verbose) {
char comm[TASK_COMM_LEN];
trace_find_cmdline(entry->pid, comm);
ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08llx]"
" %ld.%03ldms (+%ld.%03ldms): ", comm,
entry->pid, iter->cpu, entry->flags,
entry->preempt_count, iter->idx,
ns2usecs(iter->ts),
abs_usecs / USEC_PER_MSEC,
abs_usecs % USEC_PER_MSEC,
rel_usecs / USEC_PER_MSEC,
rel_usecs % USEC_PER_MSEC);
ret = trace_seq_printf(
s, "%16s %5d %3d %d %08x %08lx ",
comm, entry->pid, iter->cpu, entry->flags,
entry->preempt_count, iter->idx);
} else {
ret = lat_print_generic(s, entry, iter->cpu);
if (ret)
ret = lat_print_timestamp(s, abs_usecs, rel_usecs);
}
if (ret)
ret = lat_print_timestamp(iter, next_ts);
return ret;
}