Commit cf8e3474 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Ingo Molnar
Browse files

tracing: fix incorrect return type of ns2usecs()

Impact: fix time output bug in 32bits system

ns2usecs() returns 'long', it's incorrect.

(In i386)
          <idle>-0     [000]   521.442100: _spin_lock <-tick_do_update_jiffies64
          <idle>-0     [000]   521.442101: do_timer <-tick_do_update_jiffies64
          <idle>-0     [000]   521.442102: update_wall_time <-do_timer
          <idle>-0     [000]   521.442102: update_xtime_cache <-update_wall_time
(It always print the time less than 2200 seconds besides ...)
Because 'long' is 32bits in i386. ( (1<<31) useconds is about 2200 seconds)

          <idle>-0     [001] 4154502640.134759: rcu_bh_qsctr_inc <-__do_softirq
          <idle>-0     [001] 4154502640.134760: _local_bh_enable <-__do_softirq
          <idle>-0     [001] 4154502640.134761: idle_cpu <-irq_exit
(very large value)
Because 'long' is a signed type and it is 32bits in i386.

Changes in v2:
return 'unsigned long long' instead of 'cycle_t'
Signed-off-by: default avatarLai Jiangshan <>
LKML-Reference: <>
Reported-by: default avatarLi Zefan <>
Acked-by: default avatarFrederic Weisbecker <>
Signed-off-by: default avatarSteven Rostedt <>
Signed-off-by: default avatarIngo Molnar <>
parent 301fd748
......@@ -147,8 +147,7 @@ static int __init set_ftrace_dump_on_oops(char *str)
__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
ns2usecs(cycle_t nsec)
unsigned long long ns2usecs(cycle_t nsec)
nsec += 500;
do_div(nsec, 1000);
......@@ -596,7 +596,7 @@ extern int trace_selftest_startup_branch(struct tracer *trace,
extern void *head_page(struct trace_array_cpu *data);
extern long ns2usecs(cycle_t nsec);
extern unsigned long long ns2usecs(cycle_t nsec);
extern int
trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
extern int
......@@ -423,7 +423,7 @@ int trace_print_lat_context(struct trace_iterator *iter)
trace_find_cmdline(entry->pid, comm);
ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]"
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,
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment