On Wed, 17 Jul 2024 13:44:43 -0700
Jianfeng Wang <jianfeng.w.wang@xxxxxxxxxx> wrote:
> On 7/17/24 11:50 AM, Steven Rostedt wrote:
> > On Tue, 21 May 2024 14:37:30 -0700
> > Jianfeng Wang <jianfeng.w.wang@xxxxxxxxxx> wrote:
> >
> >> Add two internal options for fgraph: fgraph:retval-skip and
> >> fgraph:retval-hex. By default, trace-cmd will print each function's
> >> return value at the function_graph exit point, if the kernel supports
> >> the fgraph-retval feature. If users want to skip the output of
> >> functions' return values, then set fgraph:retval-skip. Alternatively,
> >> users can set fgraph:retval-hex to force the return values to be
> >> printed in hex format.
> >>
> >> Here are example commands:
> >>> trace-cmd report -O fgraph:retval-skip
> >>> trace-cmd report -O fgraph:retval-hex
> >
> > I would like to see a -O fgraph:retval-dec
> >
> > As by default most is shown in hex, having an option to do that would
> > be great.
> >
> > -- Steve
> >
> >
>
> Hi Steve,
>
> Sorry, I am confused about this.
>
> Do you suggesting adding one more option fgraph:retval-dec or
> replacing fgraph:retval-hex with fgraph:retval-dec (and making the hex
> format as the default)?
I'd be happy to add both.
>
> Currently, the patch prints return values in decimal by default
> (without any input), while users can specify fgraph:retval-hex to let
> numbers printed in hex.
It does?
I don't see that:
$ trace-cmd report
[..]
sleep-898 [006] ...1. 206.855186: funcgraph_entry: | mutex_unlock() {
sleep-898 [006] ...1. 206.855188: funcgraph_entry: 1.439 us | __mutex_unlock_slowpath(); (ret=0x0)
sleep-898 [006] ..... 206.855191: funcgraph_exit: 4.828 us | } (ret=0x0)
sleep-898 [006] ...1. 206.855192: funcgraph_entry: 0.781 us | preempt_count_add(); (ret=0x202)
sleep-898 [006] ...2. 206.855193: funcgraph_entry: | rcu_read_lock_any_held() {
sleep-898 [006] ...2. 206.855194: funcgraph_entry: 0.738 us | rcu_lockdep_current_cpu_online(); (ret=0x1)
sleep-898 [006] ...1. 206.855195: funcgraph_exit: 2.243 us | } (ret=0x1)
sleep-898 [006] ...2. 206.855196: funcgraph_entry: 0.814 us | preempt_count_sub(); (ret=0x2f3e8)
sleep-898 [006] ...1. 206.855198: funcgraph_entry: | __f_unlock_pos() {
sleep-898 [006] ...1. 206.855199: funcgraph_entry: | mutex_unlock() {
sleep-898 [006] ...1. 206.855199: funcgraph_entry: 0.851 us | __mutex_unlock_slowpath(); (ret=0x0)
sleep-898 [006] ..... 206.855201: funcgraph_exit: 2.426 us | } (ret=0x0)
sleep-898 [006] ..... 206.855202: funcgraph_exit: 3.994 us | } (ret=0x0)
> >> @@ -235,8 +249,8 @@ print_graph_entry_leaf(struct trace_seq *s,
> >> ret = trace_seq_printf(s, " (%lld)", depth);
> >>
> >> /* Return Value */
> >> - if (ret && fgraph_retval_supported) {
> >> - if (!IS_LINUX_ERR_VALUE(retval))
> >> + if (ret && fgraph_retval_supported && !fgraph_retval_skip->set) {
> >> + if (fgraph_retval_hex->set || !IS_LINUX_ERR_VALUE(retval))
It prints out hex if the value is not an error. Only errors show
decimal output.
-- Steve
> >> ret = trace_seq_printf(s, " (ret=0x%llx)", retval);
> >> else
> >> ret = trace_seq_printf(s, " (ret=%lld)", retval);
> >> @@ -385,8 +399,8 @@ fgraph_ret_handler(struct trace_seq *s, struct tep_record *record,
> >> trace_seq_printf(s, " (%lld)", depth);
> >>
> >> /* Return Value */
> >> - if (fgraph_retval_supported) {
> >> - if (!IS_LINUX_ERR_VALUE(retval))
> >> + if (fgraph_retval_supported && !fgraph_retval_skip->set) {
> >> + if (fgraph_retval_hex->set || !IS_LINUX_ERR_VALUE(retval))
> >> trace_seq_printf(s, " (ret=0x%llx)", retval);
> >> else
> >> trace_seq_printf(s, " (ret=%lld)", retval);
> >
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