[PATCH v3 13/13] perf report: add addr_from/addr_to sort dimensions

Stephane Eranian
2021-12-01T01:04:45Z

This patch adds a new pair of sorting dimensions used with branch sampling.
With the existing symbol_from/symbol_to, branches captured in the same
function would be collapsed into a single function if the latency (cycles)
was all the same. That is the case on Intel Broadwell for instance. Since
Intel Skylake, the latency is captured by hardware and therefore is used to
disambiguate branches.

This patch adds addr_from/addr_to sort dimensions that will sort branches
based on their addresses and not the function there are in. The output is
still the function name but the offset within the function is provided to
uniquely identify each branch. These new sort dimensions also help with
annotate because they create different entries in the histogram which, in
turn, generates proper branch annotation.

Here is an example using AMD's branch sampling:

$ perf record -a -b -c 1000037 -e cpu/branch-brs/ test_prg

$ perf report
Samples: 6M of event 'cpu/branch-brs/', Event count (approx.): 6901276
Overhead Command Source Shared Object Source Symbol Target Symbol Basic Block Cycle
99.65% test_prg test_prg [.] test_thread [.] test_thread -
0.02% test_prg [kernel.vmlinux] [k] asm_sysvec_apic_timer_interrupt [k] error_entry -

$ perf report -F overhead,comm,dso,addr_from,addr_to
Samples: 6M of event 'cpu/branch-brs/', Event count (approx.): 6901276
Overhead Command Shared Object Source Address Target Address
4.22% test_prg test_prg [.] test_thread+0x3c [.] test_thread+0x4
4.13% test_prg test_prg [.] test_thread+0x4 [.] test_thread+0x3a
4.09% test_prg test_prg [.] test_thread+0x3a [.] test_thread+0x6
4.08% test_prg test_prg [.] test_thread+0x2 [.] test_thread+0x3c
4.06% test_prg test_prg [.] test_thread+0x3e [.] test_thread+0x2
3.87% test_prg test_prg [.] test_thread+0x6 [.] test_thread+0x38
3.84% test_prg test_prg [.] test_thread [.] test_thread+0x3e
3.76% test_prg test_prg [.] test_thread+0x1e [.] test_thread
3.76% test_prg test_prg [.] test_thread+0x38 [.] test_thread+0x8
3.56% test_prg test_prg [.] test_thread+0x22 [.] test_thread+0x1e
3.54% test_prg test_prg [.] test_thread+0x8 [.] test_thread+0x36
3.47% test_prg test_prg [.] test_thread+0x1c [.] test_thread+0x22
3.45% test_prg test_prg [.] test_thread+0x36 [.] test_thread+0xa
3.28% test_prg test_prg [.] test_thread+0x24 [.] test_thread+0x1c
3.25% test_prg test_prg [.] test_thread+0xa [.] test_thread+0x34
3.24% test_prg test_prg [.] test_thread+0x1a [.] test_thread+0x24
3.20% test_prg test_prg [.] test_thread+0x34 [.] test_thread+0xc
3.04% test_prg test_prg [.] test_thread+0x26 [.] test_thread+0x1a
3.01% test_prg test_prg [.] test_thread+0xc [.] test_thread+0x32
2.98% test_prg test_prg [.] test_thread+0x18 [.] test_thread+0x26
2.94% test_prg test_prg [.] test_thread+0x32 [.] test_thread+0xe
2.76% test_prg test_prg [.] test_thread+0x28 [.] test_thread+0x18
2.73% test_prg test_prg [.] test_thread+0xe [.] test_thread+0x30
2.67% test_prg test_prg [.] test_thread+0x30 [.] test_thread+0x10
2.67% test_prg test_prg [.] test_thread+0x16 [.] test_thread+0x28
2.46% test_prg test_prg [.] test_thread+0x10 [.] test_thread+0x2e
2.44% test_prg test_prg [.] test_thread+0x2a [.] test_thread+0x16
2.38% test_prg test_prg [.] test_thread+0x14 [.] test_thread+0x2a
2.32% test_prg test_prg [.] test_thread+0x2e [.] test_thread+0x12
2.28% test_prg test_prg [.] test_thread+0x12 [.] test_thread+0x2c
2.16% test_prg test_prg [.] test_thread+0x2c [.] test_thread+0x14
0.02% test_prg [kernel.vmlinux] [k] asm_sysvec_apic_ti+0x5 [k] error_entry

Signed-off-by: Stephane Eranian <eranian@google.com>
---
tools/perf/util/hist.c | 2 +
tools/perf/util/hist.h | 2 +
tools/perf/util/sort.c | 128 +++++++++++++++++++++++++++++++++++++++++
tools/perf/util/sort.h | 2 +
4 files changed, 134 insertions(+)

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index b776465e04ef..bfdf64a64476 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -124,6 +124,7 @@ void hists__calc_col_len(struct hists *hists, struct hist_entry *h)
} else {
symlen = unresolved_col_width + 4 + 2;
hists__new_col_len(hists, HISTC_SYMBOL_FROM, symlen);
+ hists__new_col_len(hists, HISTC_ADDR_FROM, symlen);
hists__set_unres_dso_col_len(hists, HISTC_DSO_FROM);
}

@@ -138,6 +139,7 @@ void hists__calc_col_len(struct hists *hists, struct hist_entry *h)
} else {
symlen = unresolved_col_width + 4 + 2;
hists__new_col_len(hists, HISTC_SYMBOL_TO, symlen);
+ hists__new_col_len(hists, HISTC_ADDR_TO, symlen);
hists__set_unres_dso_col_len(hists, HISTC_DSO_TO);
}

diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index 621f35ae1efa..dbe1473adca0 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -76,6 +76,8 @@ enum hist_column {
HISTC_LOCAL_INS_LAT,
HISTC_GLOBAL_INS_LAT,
HISTC_P_STAGE_CYC,
+ HISTC_ADDR_FROM,
+ HISTC_ADDR_TO,
HISTC_NR_COLS, /* Last entry */
};

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index a111065b484e..779b65acdc02 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -990,6 +990,128 @@ struct sort_entry sort_sym_to = {
.se_width_idx = HISTC_SYMBOL_TO,
};

+static int _hist_entry__addr_snprintf(struct map_symbol *ms,
+ u64 ip, char level, char *bf, size_t size,
+ unsigned int width)
+{
+ struct symbol *sym = ms->sym;
+ struct map *map = ms->map;
+ size_t ret = 0, offs;
+
+ ret += repsep_snprintf(bf + ret, size - ret, "[%c] ", level);
+ if (sym && map) {
+ if (sym->type == STT_OBJECT) {
+ ret += repsep_snprintf(bf + ret, size - ret, "%s", sym->name);
+ ret += repsep_snprintf(bf + ret, size - ret, "+0x%llx",
+ ip - map->unmap_ip(map, sym->start));
+ } else {
+ ret += repsep_snprintf(bf + ret, size - ret, "%.*s",
+ width - ret,
+ sym->name);
+ offs = ip - sym->start;
+ if (offs)
+ ret += repsep_snprintf(bf + ret, size - ret, "+0x%llx", offs);
+ }
+ } else {
+ size_t len = BITS_PER_LONG / 4;
+ ret += repsep_snprintf(bf + ret, size - ret, "%-#.*llx",
+ len, ip);
+ }
+
+ return ret;
+}
+
+static int hist_entry__addr_from_snprintf(struct hist_entry *he, char *bf,
+ size_t size, unsigned int width)
+{
+ if (he->branch_info) {
+ struct addr_map_symbol *from = &he->branch_info->from;
+
+ return _hist_entry__addr_snprintf(&from->ms, from->al_addr,
+ he->level, bf, size, width);
+ }
+
+ return repsep_snprintf(bf, size, "%-*.*s", width, width, "N/A");
+}
+
+static int hist_entry__addr_to_snprintf(struct hist_entry *he, char *bf,
+ size_t size, unsigned int width)
+{
+ if (he->branch_info) {
+ struct addr_map_symbol *to = &he->branch_info->to;
+
+ return _hist_entry__addr_snprintf(&to->ms, to->al_addr,
+ he->level, bf, size, width);
+ }
+
+ return repsep_snprintf(bf, size, "%-*.*s", width, width, "N/A");
+}
+
+static int64_t
+sort__addr_from_cmp(struct hist_entry *left, struct hist_entry *right)
+{
+ struct addr_map_symbol *from_l;
+ struct addr_map_symbol *from_r;
+ int64_t ret;
+
+ if (!left->branch_info || !right->branch_info)
+ return cmp_null(left->branch_info, right->branch_info);
+
+ from_l = &left->branch_info->from;
+ from_r = &right->branch_info->from;
+
+ /*
+ * comparing symbol address alone is not enough since it's a
+ * relative address within a dso.
+ */
+ ret = _sort__dso_cmp(from_l->ms.map, from_r->ms.map);
+ if (ret != 0)
+ return ret;
+
+ return _sort__addr_cmp(from_l->addr, from_r->addr);
+}
+
+static int64_t
+sort__addr_to_cmp(struct hist_entry *left, struct hist_entry *right)
+{
+ struct addr_map_symbol *to_l;
+ struct addr_map_symbol *to_r;
+ int64_t ret;
+
+ if (!left->branch_info || !right->branch_info)
+ return cmp_null(left->branch_info, right->branch_info);
+
+ to_l = &left->branch_info->to;
+ to_r = &right->branch_info->to;
+
+ /*
+ * comparing symbol address alone is not enough since it's a
+ * relative address within a dso.
+ */
+ ret = _sort__dso_cmp(to_l->ms.map, to_r->ms.map);
+ if (ret != 0)
+ return ret;
+
+ return _sort__addr_cmp(to_l->addr, to_r->addr);
+}
+
+struct sort_entry sort_addr_from = {
+ .se_header = "Source Address",
+ .se_cmp = sort__addr_from_cmp,
+ .se_snprintf = hist_entry__addr_from_snprintf,
+ .se_filter = hist_entry__sym_from_filter, /* shared with sym_from */
+ .se_width_idx = HISTC_ADDR_FROM,
+};
+
+struct sort_entry sort_addr_to = {
+ .se_header = "Target Address",
+ .se_cmp = sort__addr_to_cmp,
+ .se_snprintf = hist_entry__addr_to_snprintf,
+ .se_filter = hist_entry__sym_to_filter, /* shared with sym_to */
+ .se_width_idx = HISTC_ADDR_TO,
+};
+
+
static int64_t
sort__mispredict_cmp(struct hist_entry *left, struct hist_entry *right)
{
@@ -1877,6 +1999,8 @@ static struct sort_dimension bstack_sort_dimensions[] = {
DIM(SORT_SRCLINE_FROM, "srcline_from", sort_srcline_from),
DIM(SORT_SRCLINE_TO, "srcline_to", sort_srcline_to),
DIM(SORT_SYM_IPC, "ipc_lbr", sort_sym_ipc),
+ DIM(SORT_ADDR_FROM, "addr_from", sort_addr_from),
+ DIM(SORT_ADDR_TO, "addr_to", sort_addr_to),
};

#undef DIM
@@ -3108,6 +3232,10 @@ static bool get_elide(int idx, FILE *output)
return __get_elide(symbol_conf.dso_from_list, "dso_from", output);
case HISTC_DSO_TO:
return __get_elide(symbol_conf.dso_to_list, "dso_to", output);
+ case HISTC_ADDR_FROM:
+ return __get_elide(symbol_conf.sym_from_list, "addr_from", output);
+ case HISTC_ADDR_TO:
+ return __get_elide(symbol_conf.sym_to_list, "addr_to", output);
default:
break;
}
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index 7b7145501933..b918a9eda048 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -250,6 +250,8 @@ enum sort_type {
SORT_SRCLINE_FROM,
SORT_SRCLINE_TO,
SORT_SYM_IPC,
+ SORT_ADDR_FROM,
+ SORT_ADDR_TO,

/* memory mode specific sort keys */
__SORT_MEMORY_MODE,
--
2.34.0.rc2.393.gf8c9666880-goog