by Changbin Du

[permalink] [raw]

Subject: Re: [PATCH 11/19] perf ftrace: add option '-u/--userstacktrace' to show userspace stacktrace

On Wed, May 20, 2020 at 06:07:41PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Sun, May 10, 2020 at 11:06:20PM +0800, Changbin Du escreveu:
> > This adds an option ''-u/--userstacktrace' for function tracer to display
> > userspace back trace.
>
> Probably we should have this as a term, an option to --call-graph?
>
> For --call-graph the way to suppress this is to ask for the event to be
> in the kernel only, i.e. something like:
>
> perf record -e cycles:k --call-graph
>
> So perhaps we should have something like:
>
> perf ftrace --call-graph
>
> With some default, possibly a bit different than the other perf tools,
> just including the kernel, and accepting:
>
> perf ftrace --call-graph
> perf ftrace --call-graph k
> perf ftrace --call-graph u
> perf ftrace --call-graph uk
>
> - Arnaldo
>
I just found userstacktrace is not supported by ftrace yet. It is not
hard to add this feature in kernel and I have done it locally. So I will
drop this option before it is upstreamed.

> > Signed-off-by: Changbin Du <[email protected]>
> > ---
> > tools/perf/builtin-ftrace.c | 24 ++++++++++++++++++++++++
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> > index 2ef5d1c4b23c..ab76ba66bd9e 100644
> > --- a/tools/perf/builtin-ftrace.c
> > +++ b/tools/perf/builtin-ftrace.c
> > @@ -40,6 +40,7 @@ struct perf_ftrace {
> > struct list_head nograph_funcs;
> > int graph_depth;
> > bool func_stack_trace;
> > + bool userstacktrace;
> > bool nosleep_time;
> > bool nofuncgraph_irqs;
> > bool funcgraph_tail;
> > @@ -197,6 +198,8 @@ static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
> > write_tracing_option_file("funcgraph-proc", "0");
> > write_tracing_option_file("funcgraph-abstime", "0");
> > write_tracing_option_file("irq-info", "0");
> > + write_tracing_option_file("userstacktrace", "0");
> > + write_tracing_option_file("sym-userobj", "0");
> > }
> >
> > static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
> > @@ -287,6 +290,20 @@ static int set_tracing_func_stack_trace(struct perf_ftrace *ftrace)
> > return 0;
> > }
> >
> > +static int set_tracing_userstacktrace(struct perf_ftrace *ftrace)
> > +{
> > + if (!ftrace->userstacktrace)
> > + return 0;
> > +
> > + if (write_tracing_option_file("userstacktrace", "1") < 0)
> > + return -1;
> > +
> > + if (write_tracing_option_file("sym-userobj", "1") < 0)
> > + return -1;
> > +
> > + return 0;
> > +}
> > +
> > static int reset_tracing_cpu(void)
> > {
> > struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL);
> > @@ -482,6 +499,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
> > goto out_reset;
> > }
> >
> > + if (set_tracing_userstacktrace(ftrace) < 0) {
> > + pr_err("failed to set tracing option userstacktrace\n");
> > + goto out_reset;
> > + }
> > +
> > if (set_tracing_filters(ftrace) < 0) {
> > pr_err("failed to set tracing filters\n");
> > goto out_reset;
> > @@ -644,6 +666,8 @@ int cmd_ftrace(int argc, const char **argv)
> > "do not trace given functions", parse_filter_func),
> > OPT_BOOLEAN('s', "func-stack-trace", &ftrace.func_stack_trace,
> > "Show kernel stack trace for function tracer"),
> > + OPT_BOOLEAN('u', "userstacktrace", &ftrace.userstacktrace,
> > + "Show stacktrace of the current user space thread"),
> > OPT_CALLBACK_DEFAULT('G', "graph-funcs", &ftrace.graph_funcs, "func",
> > "Set graph filter on given functions (imply to use function_graph tracer)",
> > parse_filter_func, "*"),
> > --
> > 2.25.1
> >
>
> --
>
> - Arnaldo

--
Cheers,
Changbin Du

2020-06-25 11:23:34

by Changbin Du

[permalink] [raw]

Subject: Re: [PATCH 10/19] perf ftrace: add support for trace option funcgraph-tail

Hi Arnaldo,
First appologize for so long dealy! Maybe you have forgot the context of this
serias ;)

On Wed, May 20, 2020 at 06:05:09PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Sun, May 10, 2020 at 11:06:19PM +0800, Changbin Du escreveu:
> > This adds an option '--funcgraph-tail' for function graph tracer.
>
> And I think we should make these available in a compact way, as Intel PT
> has, i.e. instead of doing something like:
>
> --function-graph-options nosleep_time,noirqs,no_tail,long_info
>
> We could have:
>
> -G ns,ni,nt,li
>
> To save on typing, or something like that.
>
I just noticed that there is an existing graph tracer option:
--graph-depth <n>

Then our new option would be:
--graph-options depth=<n>,nosleep_time,noirqs,no_tail,long_info

This makes it a little complex to parse such options (need to parse key-vale
pairs).

So can we follow the existing style instead? I mean we can have below options:
-D --graph-depth <n>
-G --graph-funcs <func>

--graph-nosleep-time
--graph-noirqs
--graph-notail
--graph-longinfo

All graph tracer options are prefixed with '--graph-'.

> - Arnaldo
>
> > Signed-off-by: Changbin Du <[email protected]>
> > ---
> > tools/perf/builtin-ftrace.c | 20 ++++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> >
> > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> > index 20bc14d6c5fb..2ef5d1c4b23c 100644
> > --- a/tools/perf/builtin-ftrace.c
> > +++ b/tools/perf/builtin-ftrace.c
> > @@ -42,6 +42,7 @@ struct perf_ftrace {
> > bool func_stack_trace;
> > bool nosleep_time;
> > bool nofuncgraph_irqs;
> > + bool funcgraph_tail;
> > bool long_info;
> > unsigned tracing_thresh;
> > };
> > @@ -192,6 +193,7 @@ static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused)
> > write_tracing_option_file("func_stack_trace", "0");
> > write_tracing_option_file("sleep-time", "1");
> > write_tracing_option_file("funcgraph-irqs", "1");
> > + write_tracing_option_file("funcgraph-tail", "0");
> > write_tracing_option_file("funcgraph-proc", "0");
> > write_tracing_option_file("funcgraph-abstime", "0");
> > write_tracing_option_file("irq-info", "0");
> > @@ -411,6 +413,17 @@ static int set_tracing_thresh(struct perf_ftrace *ftrace)
> > return 0;
> > }
> >
> > +static int set_tracing_funcgraph_tail(struct perf_ftrace *ftrace)
> > +{
> > + if (!ftrace->funcgraph_tail)
> > + return 0;
> > +
> > + if (write_tracing_option_file("funcgraph-tail", "1") < 0)
> > + return -1;
> > +
> > + return 0;
> > +}
> > +
> > static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
> > {
> > char *trace_file;
> > @@ -499,6 +512,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
> > goto out_reset;
> > }
> >
> > + if (set_tracing_funcgraph_tail(ftrace) < 0) {
> > + pr_err("failed to set tracing option funcgraph-tail\n");
> > + goto out_reset;
> > + }
> > +
> > if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
> > pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
> > goto out_reset;
> > @@ -638,6 +656,8 @@ int cmd_ftrace(int argc, const char **argv)
> > "Measure on-CPU time only (function_graph only)"),
> > OPT_BOOLEAN(0, "nofuncgraph-irqs", &ftrace.nofuncgraph_irqs,
> > "Ignore functions that happen inside interrupt (function_graph only)"),
> > + OPT_BOOLEAN(0, "funcgraph-tail", &ftrace.funcgraph_tail,
> > + "Show function tails comment (function_graph only)"),
> > OPT_BOOLEAN('l', "long-info", &ftrace.long_info,
> > "Show process names, PIDs, timestamps, irq-info if available"),
> > OPT_UINTEGER(0, "tracing-thresh", &ftrace.tracing_thresh,
> > --
> > 2.25.1
> >
>
> --
>
> - Arnaldo

--
Cheers,
Changbin Du