perf trace: Allow configuring if zeroed syscall args should be printed

The default so far, since we show argument names followed by its values,
was to make the output more compact by suppressing most zeroed args.

Make this configurable so that users can choose what best suit their
needs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-q0gxws02ygodh94o0hzim5xd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 423cb41..b55bd16 100644 (file)
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -528,6 +528,8 @@ trace.*::
                The initial use case is to add augmented_raw_syscalls.o to
                activate the 'perf trace' logic that looks for syscall
                pointer contents after the normal tracepoint payload.
+       trace.show_zeros::
+               Do not suppress syscall arguments that are equal to zero.
 
 SEE ALSO
 --------

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index d754a74..4d97bda 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -127,6 +127,7 @@ struct trace {
        bool                    show_tool_stats;
        bool                    trace_syscalls;
        bool                    kernel_syscallchains;
+       bool                    show_zeros;
        bool                    force;
        bool                    vfs_getname;
        int                     trace_pgfaults;
@@ -1598,6 +1599,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
                         * strarray for it.
                         */
                        if (val == 0 &&
+                           !trace->show_zeros &&
                            !(sc->arg_fmt &&
                              (sc->arg_fmt[arg.idx].show_zero ||
                               sc->arg_fmt[arg.idx].scnprintf == SCA_STRARRAY ||
@@ -3526,14 +3528,16 @@ static void trace__set_bpf_map_syscalls(struct trace *trace)
 
 static int trace__config(const char *var, const char *value, void *arg)
 {
+       struct trace *trace = arg;
        int err = 0;
 
        if (!strcmp(var, "trace.add_events")) {
-               struct trace *trace = arg;
                struct option o = OPT_CALLBACK('e', "event", &trace->evlist, "event",
                                               "event selector. use 'perf list' to list available events",
                                               parse_events_option);
                err = parse_events_option(&o, value, 0);
+       } else if (!strcmp(var, "trace.show_zeros")) {
+               trace->show_zeros = perf_config_bool(var, value);
        }
 
        return err;