perf script: Enable printing of branch stack

This patch improves perf script by enabling printing of the
branch stack via the 'brstack' and 'brstacksym' arguments to
the field selection option -F. The option is off by default
and operates only if the perf.data file has branch stack content.

The branches are printed in to/from pairs. The most recent branch
is printed first. The number of branch entries vary based on the
underlying hardware and filtering used.

The brstack prints FROM/TO addresses in raw hexadecimal format.
The brstacksym prints FROM/TO addresses in symbolic form wherever
possible.

 $ perf script -F ip,brstack
  5d3000 0x401aa0/0x5d2000/M/-/-/-/0 ...

 $ perf script -F ip,brstacksym
  4011e0 noploop+0x0/noploop+0x0/P/-/-/0

The notation F/T/M/X/A/C describes the attributes of the branch.
F=from, T=to, M/P=misprediction/prediction, X=TSX, A=TSX abort, C=cycles (SKL)

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yuanfang Chen <cyfmxc@gmail.com>
Link: http://lkml.kernel.org/r/1441039273-16260-5-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index b3b42f9..382ddfb 100644 (file)
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -112,11 +112,11 @@ OPTIONS
 --debug-mode::
         Do various checks like samples ordering and lost events.
 
--f::
+-F::
 --fields::
         Comma separated list of fields to print. Options are:
         comm, tid, pid, time, cpu, event, trace, ip, sym, dso, addr, symoff,
-       srcline, period, iregs, flags.
+       srcline, period, iregs, brstack, brstacksym, flags.
         Field list can be prepended with the type, trace, sw or hw,
         to indicate to which event type the field list applies.
         e.g., -f sw:comm,tid,time,ip,sym  and -f trace:time,cpu,trace
@@ -175,6 +175,16 @@ OPTIONS
        Finally, a user may not set fields to none for all event types.
        i.e., -f "" is not allowed.
 
+       The brstack output includes branch related information with raw addresses using the
+       /v/v/v/v/ syntax in the following order:
+       FROM: branch source instruction
+       TO  : branch target instruction
+        M/P/-: M=branch target mispredicted or branch direction was mispredicted, P=target predicted or direction predicted, -=not supported
+       X/- : X=branch inside a transactional region, -=not in transaction region or not supported
+       A/- : A=TSX abort entry, -=not aborted region or not supported
+
+       The brstacksym is identical to brstack, except that the FROM and TO addresses are printed in a symbolic form if possible.
+
 -k::
 --vmlinux=<file>::
         vmlinux pathname

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 278acb2..72b5deb 100644 (file)
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -51,6 +51,8 @@ enum perf_output_field {
        PERF_OUTPUT_SRCLINE         = 1U << 12,
        PERF_OUTPUT_PERIOD          = 1U << 13,
        PERF_OUTPUT_IREGS           = 1U << 14,
+       PERF_OUTPUT_BRSTACK         = 1U << 15,
+       PERF_OUTPUT_BRSTACKSYM      = 1U << 16,
 };
 
 struct output_option {
@@ -72,6 +74,8 @@ struct output_option {
        {.str = "srcline", .field = PERF_OUTPUT_SRCLINE},
        {.str = "period", .field = PERF_OUTPUT_PERIOD},
        {.str = "iregs", .field = PERF_OUTPUT_IREGS},
+       {.str = "brstack", .field = PERF_OUTPUT_BRSTACK},
+       {.str = "brstacksym", .field = PERF_OUTPUT_BRSTACKSYM},
 };
 
 /* default set to maintain compatibility with current format */
@@ -425,6 +429,77 @@ static void print_sample_start(struct perf_sample *sample,
        }
 }
 
+static inline char
+mispred_str(struct branch_entry *br)
+{
+       if (!(br->flags.mispred  || br->flags.predicted))
+               return '-';
+
+       return br->flags.predicted ? 'P' : 'M';
+}
+
+static void print_sample_brstack(union perf_event *event __maybe_unused,
+                         struct perf_sample *sample,
+                         struct thread *thread __maybe_unused,
+                         struct perf_event_attr *attr __maybe_unused)
+{
+       struct branch_stack *br = sample->branch_stack;
+       u64 i;
+
+       if (!(br && br->nr))
+               return;
+
+       for (i = 0; i < br->nr; i++) {
+               printf(" 0x%"PRIx64"/0x%"PRIx64"/%c/%c/%c/%d ",
+                       br->entries[i].from,
+                       br->entries[i].to,
+                       mispred_str( br->entries + i),
+                       br->entries[i].flags.in_tx? 'X' : '-',
+                       br->entries[i].flags.abort? 'A' : '-',
+                       br->entries[i].flags.cycles);
+       }
+}
+
+static void print_sample_brstacksym(union perf_event *event __maybe_unused,
+                         struct perf_sample *sample,
+                         struct thread *thread __maybe_unused,
+                         struct perf_event_attr *attr __maybe_unused)
+{
+       struct branch_stack *br = sample->branch_stack;
+       struct addr_location alf, alt;
+       u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+       u64 i, from, to;
+
+       if (!(br && br->nr))
+               return;
+
+       for (i = 0; i < br->nr; i++) {
+
+               memset(&alf, 0, sizeof(alf));
+               memset(&alt, 0, sizeof(alt));
+               from = br->entries[i].from;
+               to   = br->entries[i].to;
+
+               thread__find_addr_map(thread, cpumode, MAP__FUNCTION, from, &alf);
+               if (alf.map)
+                       alf.sym = map__find_symbol(alf.map, alf.addr, NULL);
+
+               thread__find_addr_map(thread, cpumode, MAP__FUNCTION, to, &alt);
+               if (alt.map)
+                       alt.sym = map__find_symbol(alt.map, alt.addr, NULL);
+
+               symbol__fprintf_symname_offs(alf.sym, &alf, stdout);
+               putchar('/');
+               symbol__fprintf_symname_offs(alt.sym, &alt, stdout);
+               printf("/%c/%c/%c/%d ",
+                       mispred_str( br->entries + i),
+                       br->entries[i].flags.in_tx? 'X' : '-',
+                       br->entries[i].flags.abort? 'A' : '-',
+                       br->entries[i].flags.cycles);
+       }
+}
+
+
 static void print_sample_addr(union perf_event *event,
                          struct perf_sample *sample,
                          struct thread *thread,
@@ -560,6 +635,11 @@ static void process_event(union perf_event *event, struct perf_sample *sample,
        if (PRINT_FIELD(IREGS))
                print_sample_iregs(event, sample, thread, attr);
 
+       if (PRINT_FIELD(BRSTACK))
+               print_sample_brstack(event, sample, thread, attr);
+       else if (PRINT_FIELD(BRSTACKSYM))
+               print_sample_brstacksym(event, sample, thread, attr);
+
        printf("\n");
 }
 
@@ -1681,7 +1761,7 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
                     "comma separated output fields prepend with 'type:'. "
                     "Valid types: hw,sw,trace,raw. "
                     "Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso,"
-                    "addr,symoff,period,iregs,flags", parse_output_fields),
+                    "addr,symoff,period,iregs,brstack,brstacksym,flags", parse_output_fields),
        OPT_BOOLEAN('a', "all-cpus", &system_wide,
                    "system-wide collection from all CPUs"),
        OPT_STRING('S', "symbols", &symbol_conf.sym_list_str, "symbol[,symbol...]",