When callgraph is enabled, the append_chain() function consumes a major
portion of the total CPU time. This patch tries to streamline the
append_chain() function by removing unneeded conditional test as well as
using ?: statement which can be more efficient than the regular if
statement in some architectures.
Signed-off-by: Waiman Long <waiman.l...@hp.com>
---
tools/perf/util/callchain.c | 9 ++++-----
1 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 482f680..1e79001 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -315,6 +315,7 @@ append_chain(struct callchain_node *root,
struct callchain_list *cnode;
u64 start = cursor->pos;
bool found = false;
+ bool func_mode = (callchain_param.key == CCKEY_FUNCTION);
u64 matches;
/*
@@ -331,17 +332,15 @@ append_chain(struct callchain_node *root,
if (!node)
break;
- sym = node->sym;
+ sym = func_mode ? node->sym : NULL;
- if (cnode->ms.sym && sym &&
- callchain_param.key == CCKEY_FUNCTION) {
+ if (cnode->ms.sym && sym) {
if (cnode->ms.sym->start != sym->start)
break;
} else if (cnode->ip != node->ip)
break;
- if (!found)
- found = true;
+ found = true;
callchain_cursor_advance(cursor);
}
--
1.7.1
--
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