From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Ingo Molnar <mingo@elte.hu>, Steven Rostedt <srostedt@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Li Zefan <lizf@cn.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] tracing: fix incorrect return type of ns2usecs() V2
Date: Mon, 30 Mar 2009 13:48:00 +0800 [thread overview]
Message-ID: <49D05D10.4030009@cn.fujitsu.com> (raw)
In-Reply-To: <49D041ED.1060007@cn.fujitsu.com>
Impact: fix time output bug in 32bits system
ns2usecs() returns 'long', it's incorrect.
(In i386)
# cat trace
...
<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)
# cat trace
...
<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.
Changed from V1:
return 'unsigned long long' instead of 'cycle_t'
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
---
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a81dec..5232201 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -147,8 +147,7 @@ static int __init set_ftrace_dump_on_oops(char *str)
}
__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
-long
-ns2usecs(cycle_t nsec)
+unsigned long long ns2usecs(cycle_t nsec)
{
nsec += 500;
do_div(nsec, 1000);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index fec6521..47aa6d0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -602,7 +602,7 @@ extern int trace_selftest_startup_branch(struct tracer *trace,
#endif /* CONFIG_FTRACE_STARTUP_TEST */
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
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index aeac358..0e70fb0 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -433,7 +433,7 @@ 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,
next prev parent reply other threads:[~2009-03-30 5:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-30 3:52 [PATCH] tracing: fix incorrect return type of ns2usecs() Lai Jiangshan
2009-03-30 5:48 ` Lai Jiangshan [this message]
2009-04-03 16:13 ` [PATCH] tracing: fix incorrect return type of ns2usecs() V2 Steven Rostedt
2009-04-07 13:12 ` [tip:tracing/urgent] tracing: fix incorrect return type of ns2usecs() Lai Jiangshan
2009-03-30 9:55 ` [PATCH] " Frederic Weisbecker
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