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Subject[PATCH v3 1/6] perf report: Add branch flag to callchain cursor node
Date
Since the branch ip has been added to call stack for easier browsing,
this patch adds more branch information. For example, add a flag to
indicate if this ip is a branch, and also add with the branch flag.

Then we can know if the cursor node represents a branch and know
what the branch flag it has.

The branch history code has a loop detection pass that removes small
loops. It would be nice for knowing how many loops were removed.
This patch records the number of removed loops in a callchain cursor
node.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
tools/perf/util/callchain.c | 13 +++++++--
tools/perf/util/callchain.h | 7 ++++-
tools/perf/util/machine.c | 69 ++++++++++++++++++++++++++++++++++-----------
3 files changed, 70 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 07fd30b..7857494 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -730,7 +730,8 @@ merge_chain_branch(struct callchain_cursor *cursor,

list_for_each_entry_safe(list, next_list, &src->val, list) {
callchain_cursor_append(cursor, list->ip,
- list->ms.map, list->ms.sym);
+ list->ms.map, list->ms.sym,
+ false, NULL, 0);
list_del(&list->list);
free(list);
}
@@ -767,7 +768,9 @@ int callchain_merge(struct callchain_cursor *cursor,
}

int callchain_cursor_append(struct callchain_cursor *cursor,
- u64 ip, struct map *map, struct symbol *sym)
+ u64 ip, struct map *map, struct symbol *sym,
+ bool branch, struct branch_flags *flags,
+ int removed_loop)
{
struct callchain_cursor_node *node = *cursor->last;

@@ -782,6 +785,12 @@ int callchain_cursor_append(struct callchain_cursor *cursor,
node->ip = ip;
node->map = map;
node->sym = sym;
+ node->branch = branch;
+ node->removed_loop = removed_loop;
+
+ if (flags)
+ memcpy(&node->branch_flags, flags,
+ sizeof(struct branch_flags));

cursor->nr++;

diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 13e7554..a16da59 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -129,6 +129,9 @@ struct callchain_cursor_node {
u64 ip;
struct map *map;
struct symbol *sym;
+ bool branch;
+ struct branch_flags branch_flags;
+ int removed_loop;
struct callchain_cursor_node *next;
};

@@ -183,7 +186,9 @@ static inline void callchain_cursor_reset(struct callchain_cursor *cursor)
}

int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip,
- struct map *map, struct symbol *sym);
+ struct map *map, struct symbol *sym,
+ bool branch, struct branch_flags *flags,
+ int removed_loop);

/* Close a cursor writing session. Initialize for the reader */
static inline void callchain_cursor_commit(struct callchain_cursor *cursor)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index df85b9e..7c44331 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1616,7 +1616,10 @@ static int add_callchain_ip(struct thread *thread,
struct symbol **parent,
struct addr_location *root_al,
u8 *cpumode,
- u64 ip)
+ u64 ip,
+ bool branch,
+ struct branch_flags *flags,
+ int removed_loop)
{
struct addr_location al;

@@ -1668,7 +1671,8 @@ static int add_callchain_ip(struct thread *thread,

if (symbol_conf.hide_unresolved && al.sym == NULL)
return 0;
- return callchain_cursor_append(cursor, al.addr, al.map, al.sym);
+ return callchain_cursor_append(cursor, al.addr, al.map, al.sym,
+ branch, flags, removed_loop);
}

struct branch_info *sample__resolve_bstack(struct perf_sample *sample,
@@ -1696,12 +1700,13 @@ struct branch_info *sample__resolve_bstack(struct perf_sample *sample,
#define PERF_MAX_BRANCH_DEPTH 127

/* Remove loops. */
-static int remove_loops(struct branch_entry *l, int nr)
+static int remove_loops(struct branch_entry *l, int nr, int *removed)
{
int i, j, off;
unsigned char chash[CHASHSZ];

memset(chash, NO_ENTRY, sizeof(chash));
+ *removed = 0;

BUG_ON(PERF_MAX_BRANCH_DEPTH > 255);

@@ -1724,6 +1729,7 @@ static int remove_loops(struct branch_entry *l, int nr)
memmove(l + i, l + i + off,
(nr - (i + off)) * sizeof(*l));
nr -= off;
+ *removed += 1;
}
}
}
@@ -1757,7 +1763,9 @@ static int resolve_lbr_callchain_sample(struct thread *thread,
/* LBR only affects the user callchain */
if (i != chain_nr) {
struct branch_stack *lbr_stack = sample->branch_stack;
- int lbr_nr = lbr_stack->nr, j;
+ int lbr_nr = lbr_stack->nr, j, k;
+ bool branch;
+ struct branch_flags *flags;
/*
* LBR callstack can only get user call chain.
* The mix_chain_nr is kernel call chain
@@ -1772,23 +1780,41 @@ static int resolve_lbr_callchain_sample(struct thread *thread,

for (j = 0; j < mix_chain_nr; j++) {
int err;
+ branch = false;
+ flags = NULL;
+
if (callchain_param.order == ORDER_CALLEE) {
if (j < i + 1)
ip = chain->ips[j];
- else if (j > i + 1)
- ip = lbr_stack->entries[j - i - 2].from;
- else
+ else if (j > i + 1) {
+ k = j - i - 2;
+ ip = lbr_stack->entries[k].from;
+ branch = true;
+ flags = &lbr_stack->entries[k].flags;
+ } else {
ip = lbr_stack->entries[0].to;
+ branch = true;
+ flags = &lbr_stack->entries[0].flags;
+ }
} else {
- if (j < lbr_nr)
- ip = lbr_stack->entries[lbr_nr - j - 1].from;
+ if (j < lbr_nr) {
+ k = lbr_nr - j - 1;
+ ip = lbr_stack->entries[k].from;
+ branch = true;
+ flags = &lbr_stack->entries[k].flags;
+ }
else if (j > lbr_nr)
ip = chain->ips[i + 1 - (j - lbr_nr)];
- else
+ else {
ip = lbr_stack->entries[0].to;
+ branch = true;
+ flags = &lbr_stack->entries[0].flags;
+ }
}

- err = add_callchain_ip(thread, cursor, parent, root_al, &cpumode, ip);
+ err = add_callchain_ip(thread, cursor, parent,
+ root_al, &cpumode, ip,
+ branch, flags, 0);
if (err)
return (err < 0) ? err : 0;
}
@@ -1813,6 +1839,7 @@ static int thread__resolve_callchain_sample(struct thread *thread,
int i, j, err, nr_entries;
int skip_idx = -1;
int first_call = 0;
+ int removed_loop, removed;

if (perf_evsel__has_branch_callstack(evsel)) {
err = resolve_lbr_callchain_sample(thread, cursor, sample, parent,
@@ -1868,14 +1895,21 @@ static int thread__resolve_callchain_sample(struct thread *thread,
be[i] = branch->entries[branch->nr - i - 1];
}

- nr = remove_loops(be, nr);
+ nr = remove_loops(be, nr, &removed);
+ removed_loop = 0;

for (i = 0; i < nr; i++) {
+ if (i == nr - 1)
+ removed_loop = removed;
+
err = add_callchain_ip(thread, cursor, parent, root_al,
- NULL, be[i].to);
+ NULL, be[i].to,
+ true, &be[i].flags,
+ removed_loop);
if (!err)
err = add_callchain_ip(thread, cursor, parent, root_al,
- NULL, be[i].from);
+ NULL, be[i].from,
+ true, &be[i].flags, 0);
if (err == -EINVAL)
break;
if (err)
@@ -1903,7 +1937,9 @@ static int thread__resolve_callchain_sample(struct thread *thread,
if (ip < PERF_CONTEXT_MAX)
++nr_entries;

- err = add_callchain_ip(thread, cursor, parent, root_al, &cpumode, ip);
+ err = add_callchain_ip(thread, cursor, parent,
+ root_al, &cpumode, ip,
+ false, NULL, 0);

if (err)
return (err < 0) ? err : 0;
@@ -1919,7 +1955,8 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
if (symbol_conf.hide_unresolved && entry->sym == NULL)
return 0;
return callchain_cursor_append(cursor, entry->ip,
- entry->map, entry->sym);
+ entry->map, entry->sym,
+ false, NULL, 0);
}

static int thread__resolve_callchain_unwind(struct thread *thread,
--
2.7.4
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