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Date: Fri, 24 Feb 2012 10:40:48 +0100
From: Stephane Eranian <eranian@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: acme@...hat.com, peterz@...radead.org, mingo@...e.hu,
dsahern@...il.com, ravitillo@....gov, khandual@...ux.vnet.ibm.com,
asharma@...com, robert.richter@....com, ming.m.lin@...el.com,
vweaver1@...s.utk.edu, andi@...stfloor.org
Subject: [PATCH] perf report: auto-detect branch stack sampling mode
This patch adds auto-detection of samples with taken branch stacks.
The auto-detection avoids having to specify the -b or --branch-stack
option on the cmdline.
The patch adds a new feature bit HEADER_BRANCH_STACK to mark the
presence of branch stacks in samples.
You can now do:
$ perf record -b any noploop 2
$ perf report
# Events: 8K cycles
#
# Overhead Command Source Shared Object Source Symbol Target Shared Object Target Symbol
# ........ ....... .................... ................... .................... ..................
#
91.56% noploop noploop [.] noploop noploop [.] noploop
0.42% noploop [kernel.kallsyms] [k] __lock_acquire [kernel.kallsyms] [k] __lock_acquire
To force regular reporting based on the instruction address:
$ perf report --no-branch-stack
#
# Events: 2K cycles
#
# Overhead Command Shared Object Symbol
# ........ ....... ................. ...............................
#
92.03% noploop noploop [.] noploop
1.00% noploop [kernel.kallsyms] [k] lock_acquire
Signed-off-by: Stephane Eranian <eranian@...gle.com>
---
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 1c49d4e..5e833a2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -473,6 +473,9 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
if (!have_tracepoints(&evsel_list->entries))
perf_header__clear_feat(&session->header, HEADER_TRACE_INFO);
+ if (!rec->opts.branch_stack)
+ perf_header__clear_feat(&session->header, HEADER_BRANCH_STACK);
+
if (!rec->file_new) {
err = perf_session__read_header(session, output);
if (err < 0)
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 528789f..edd4289 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -306,21 +306,14 @@ static int __cmd_report(struct perf_report *rep)
{
int ret = -EINVAL;
u64 nr_samples;
- struct perf_session *session;
struct perf_evsel *pos;
+ struct perf_session *session = rep->session;
struct map *kernel_map;
struct kmap *kernel_kmap;
const char *help = "For a higher level overview, try: perf report --sort comm,dso";
signal(SIGINT, sig_handler);
- session = perf_session__new(rep->input_name, O_RDONLY,
- rep->force, false, &rep->tool);
- if (session == NULL)
- return -ENOMEM;
-
- rep->session = session;
-
if (rep->cpu_list) {
ret = perf_session__cpu_bitmap(session, rep->cpu_list,
rep->cpu_bitmap);
@@ -489,7 +482,10 @@ parse_callchain_opt(const struct option *opt, const char *arg, int unset)
int cmd_report(int argc, const char **argv, const char *prefix __used)
{
+ struct perf_session *session;
struct stat st;
+ bool has_br_stack;
+ int ret = -1;
char callchain_default_opt[] = "fractal,0.5,callee";
const char * const report_usage[] = {
"perf report [<options>]",
@@ -600,7 +596,23 @@ int cmd_report(int argc, const char **argv, const char *prefix __used)
report.input_name = "perf.data";
}
- if (sort__branch_mode) {
+ session = perf_session__new(report.input_name, O_RDONLY,
+ report.force, false, &report.tool);
+ if (session == NULL)
+ return -ENOMEM;
+
+ report.session = session;
+
+ has_br_stack = perf_header__has_feat(&session->header,
+ HEADER_BRANCH_STACK);
+
+ /*
+ * if branch mode set by user via -b or --branch-stack
+ * or not forced off by user (-no-branch-stack) user and present
+ * in the file then we set branch mode
+ */
+ if (sort__branch_mode || (sort__branch_mode == -1 && has_br_stack)) {
+ sort__branch_mode = true;
if (use_browser)
fprintf(stderr, "Warning: TUI interface not supported"
" in branch mode\n");
@@ -657,13 +669,13 @@ int cmd_report(int argc, const char **argv, const char *prefix __used)
}
if (symbol__init() < 0)
- return -1;
+ goto error;
setup_sorting(report_usage, options);
if (parent_pattern != default_parent_pattern) {
if (sort_dimension__add("parent") < 0)
- return -1;
+ goto error;
/*
* Only show the parent fields if we explicitly
@@ -685,5 +697,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __used)
sort_entry__setup_elide(&sort_comm, symbol_conf.comm_list, "comm", stdout);
sort_entry__setup_elide(&sort_sym, symbol_conf.sym_list, "symbol", stdout);
- return __cmd_report(&report);
+ ret = __cmd_report(&report);
+error:
+ perf_session__delete(session);
+ return ret;
}
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index c851495..c22491e 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1023,6 +1023,12 @@ static int write_cpuid(int fd, struct perf_header *h __used,
return do_write_string(fd, buffer);
}
+static int write_branch_stack(int fd __used, struct perf_header *h __used,
+ struct perf_evlist *evlist __used)
+{
+ return 0;
+}
+
static void print_hostname(struct perf_header *ph, int fd, FILE *fp)
{
char *str = do_read_string(fd, ph);
@@ -1315,6 +1321,12 @@ static void print_cpuid(struct perf_header *ph, int fd, FILE *fp)
free(str);
}
+static void print_branch_stack(struct perf_header *ph __used, int fd __used,
+ FILE *fp)
+{
+ fprintf(fp, "# contains samples with branch stacks\n");
+}
+
static int __event_process_build_id(struct build_id_event *bev,
char *filename,
struct perf_session *session)
@@ -1519,6 +1531,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
FEAT_OPA(HEADER_CMDLINE, cmdline),
FEAT_OPF(HEADER_CPU_TOPOLOGY, cpu_topology),
FEAT_OPF(HEADER_NUMA_TOPOLOGY, numa_topology),
+ FEAT_OPA(HEADER_BRANCH_STACK, branch_stack),
};
struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index e68f617..21a6be0 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -27,7 +27,7 @@ enum {
HEADER_EVENT_DESC,
HEADER_CPU_TOPOLOGY,
HEADER_NUMA_TOPOLOGY,
-
+ HEADER_BRANCH_STACK,
HEADER_LAST_FEATURE,
HEADER_FEAT_BITS = 256,
};
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 2739ed1..69d50c0 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -8,7 +8,7 @@ const char default_sort_order[] = "comm,dso,symbol";
const char *sort_order = default_sort_order;
int sort__need_collapse = 0;
int sort__has_parent = 0;
-bool sort__branch_mode;
+bool sort__branch_mode = -1; /* -1 = means not set */
enum sort_type sort__first_dimension;
--
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