[sysprof] Add FIXME about performance issue in stack_stash_add_trace()

[Søren Sandmann Pedersen <ssp src gnome org>]

commit 298f92ff2033b392bfd16dabb4591db4d7164735
Author: Søren Sandmann Pedersen <sandmann daimi au dk>
Date:   Fri Apr 23 11:26:17 2010 -0400

    Add FIXME about performance issue in stack_stash_add_trace()

 stackstash.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/stackstash.c b/stackstash.c
index 8c06f7b..44912e4 100644
--- a/stackstash.c
+++ b/stackstash.c
@@ -220,6 +220,13 @@ stack_stash_add_trace (StackStash *stash,
 	StackNode *match = NULL;
 	StackNode *prev;
 
+	/* FIXME: On x86-64 we don't get proper stacktraces which means
+	 * each node can have tons of children. That makes this loop
+	 * here show up on profiles.
+	 *
+	 * Not sure what can be done about it aside from actually fixing
+	 * x86-64 to get stacktraces.
+	 */
 	prev = NULL;
 	for (match = *location; match; prev = match, match = match->siblings)
 	{