Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Fri, 14 Aug 2020 09:24:40 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v8 08/18] perf ftrace: add support for tracing option 'func_stack_trace' |
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Em Sat, Aug 08, 2020 at 10:31:31AM +0800, Changbin Du escreveu: > This adds support to display call trace for function tracer. To do this, > just specify a '--func-opts call-graph' option.
Applied, thanks for providing the usage example and the output of the tool, please consider making this more compact and similar to the other perf tools as:
# perf ftrace -g -T vfs_read
# perf report -h -g
Usage: perf report [<options>]
-g, --call-graph <print_type,threshold[,print_limit],order,sort_key[,branch],value> Display call graph (stack chain/backtrace):
print_type: call graph printing style (graph|flat|fractal|folded|none) threshold: minimum call graph inclusion threshold (<percent>) print_limit: maximum number of call graph entry (<number>) order: call graph order (caller|callee) sort_key: call graph sort key (function|address) branch: include last branch info to call graph (branch) value: call graph value (percent|period|count) Default: graph,0.5,caller,function,percent #
Is there a way to ask for a limit in the number of levels? That is similar to /proc/sys/kernel/perf_event_max_stack (system wide) and perf_event_attr.sample_max_stack (per event)?
One can ask for that per event:
# perf trace -e sched:*_wakeup/max-stack=2/ -e sched:*switch/max-stack=5/ --max-events=4 0.000 migration/0/12 sched:sched_switch(prev_comm: "migration/0", prev_pid: 12 (migration/0), prev_prio: 0, prev_state: 1, next_comm: "swapper/0", next_pid: 0, next_prio: 120) __schedule ([kernel.kallsyms]) __schedule ([kernel.kallsyms]) schedule ([kernel.kallsyms]) smpboot_thread_fn ([kernel.kallsyms]) kthread ([kernel.kallsyms]) 2.381 :0/0 sched:sched_wakeup(comm: "PacerThread", pid: 111637 (PacerThread), prio: 120, success: 1, target_cpu: 0) ttwu_do_wakeup ([kernel.kallsyms]) ttwu_do_wakeup ([kernel.kallsyms]) 2.387 :0/0 sched:sched_switch(prev_comm: "swapper/0", prev_pid: 0, prev_prio: 120, prev_state: 0, next_comm: "PacerThread", next_pid: 111637 (PacerThread), next_prio: 120) __schedule ([kernel.kallsyms]) __schedule ([kernel.kallsyms]) schedule_idle ([kernel.kallsyms]) do_idle ([kernel.kallsyms]) cpu_startup_entry ([kernel.kallsyms]) 2.410 PacerThread/111637 sched:sched_switch(prev_comm: "PacerThread", prev_pid: 111637 (PacerThread), prev_prio: 120, prev_state: 1, next_comm: "swapper/0", next_pid: 0, next_prio: 120) __schedule ([kernel.kallsyms]) __schedule ([kernel.kallsyms]) schedule ([kernel.kallsyms]) futex_wait_queue_me ([kernel.kallsyms]) futex_wait ([kernel.kallsyms]) #
- Arnaldo > $ sudo perf ftrace -T vfs_read --func-opts call-graph > iio-sensor-prox-855 [003] 6168.369657: vfs_read <-ksys_read > iio-sensor-prox-855 [003] 6168.369677: <stack trace> > => vfs_read > => ksys_read > => __x64_sys_read > => do_syscall_64 > => entry_SYSCALL_64_after_hwframe > ... > > Signed-off-by: Changbin Du <changbin.du@gmail.com> > > --- > v3: switch to uniform option --func-opts. > v2: option name '-s' -> '--func-call-graph' > --- > tools/perf/Documentation/perf-ftrace.txt | 4 +++ > tools/perf/builtin-ftrace.c | 42 ++++++++++++++++++++++++ > 2 files changed, 46 insertions(+) > > diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt > index c46d0a09b38c..8f08ad0992c2 100644 > --- a/tools/perf/Documentation/perf-ftrace.txt > +++ b/tools/perf/Documentation/perf-ftrace.txt > @@ -76,6 +76,10 @@ OPTIONS > specify multiple functions (or glob patterns). It will be > passed to 'set_ftrace_notrace' in tracefs. > > +--func-opts:: > + List of options allowed to set: > + call-graph - Display kernel stack trace for function tracer. > + > -G:: > --graph-funcs=:: > Select function_graph tracer and set graph filter on the given > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c > index 07b81d0c1658..469b89748c42 100644 > --- a/tools/perf/builtin-ftrace.c > +++ b/tools/perf/builtin-ftrace.c > @@ -27,6 +27,7 @@ > #include "util/cap.h" > #include "util/config.h" > #include "util/units.h" > +#include "util/parse-sublevel-options.h" > > #define DEFAULT_TRACER "function_graph" > > @@ -42,6 +43,7 @@ struct perf_ftrace { > int graph_depth; > unsigned long percpu_buffer_size; > bool inherit; > + int func_stack_trace; > }; > > struct filter_entry { > @@ -202,6 +204,7 @@ static void reset_tracing_filters(void); > static void reset_tracing_options(struct perf_ftrace *ftrace __maybe_unused) > { > write_tracing_option_file("function-fork", "0"); > + write_tracing_option_file("func_stack_trace", "0"); > } > > static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) > @@ -278,6 +281,17 @@ static int set_tracing_cpu(struct perf_ftrace *ftrace) > return set_tracing_cpumask(cpumap); > } > > +static int set_tracing_func_stack_trace(struct perf_ftrace *ftrace) > +{ > + if (!ftrace->func_stack_trace) > + return 0; > + > + if (write_tracing_option_file("func_stack_trace", "1") < 0) > + return -1; > + > + return 0; > +} > + > static int reset_tracing_cpu(void) > { > struct perf_cpu_map *cpumap = perf_cpu_map__new(NULL); > @@ -426,6 +440,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) > goto out_reset; > } > > + if (set_tracing_func_stack_trace(ftrace) < 0) { > + pr_err("failed to set tracing option func_stack_trace\n"); > + goto out_reset; > + } > + > if (set_tracing_filters(ftrace) < 0) { > pr_err("failed to set tracing filters\n"); > goto out_reset; > @@ -598,6 +617,26 @@ static int parse_buffer_size(const struct option *opt, > return -1; > } > > +static int parse_func_tracer_opts(const struct option *opt, > + const char *str, int unset) > +{ > + int ret; > + struct perf_ftrace *ftrace = (struct perf_ftrace *) opt->value; > + struct sublevel_option func_tracer_opts[] = { > + { .name = "call-graph", .value_ptr = &ftrace->func_stack_trace }, > + { .name = NULL, } > + }; > + > + if (unset) > + return 0; > + > + ret = perf_parse_sublevel_options(str, func_tracer_opts); > + if (ret) > + return ret; > + > + return 0; > +} > + > static void select_tracer(struct perf_ftrace *ftrace) > { > bool graph = !list_empty(&ftrace->graph_funcs) || > @@ -645,6 +684,9 @@ int cmd_ftrace(int argc, const char **argv) > parse_filter_func), > OPT_CALLBACK('N', "notrace-funcs", &ftrace.notrace, "func", > "do not trace given functions", parse_filter_func), > + OPT_CALLBACK(0, "func-opts", &ftrace, "options", > + "function tracer options, available options: call-graph", > + parse_func_tracer_opts), > OPT_CALLBACK('G', "graph-funcs", &ftrace.graph_funcs, "func", > "trace given functions using function_graph tracer", > parse_filter_func), > -- > 2.25.1 >
--
- Arnaldo
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