From c16c606cffd19b19720e0e0966a87050ed5bf7e3 Mon Sep 17 00:00:00 2001
From: Russell Bryant <russell@russellbryant.com>
Date: Tue, 28 Nov 2006 23:13:37 +0000
Subject: [PATCH] Add a comment to note near some code that performs a very
expensive operation that occurs for every incoming media frame.
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@48099 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
channels/chan_iax2.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index f7cdcb2891..78bf747c52 100644
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -1195,6 +1195,20 @@ static int make_trunk(unsigned short callno, int locked)
return res;
}
+/*!
+ * \todo XXX Note that this function contains a very expensive operation that
+ * happens for *every* incoming media frame. It iterates through every
+ * possible call number, locking and unlocking each one, to try to match the
+ * incoming frame to an active call. Call numbers can be up to 2^15, 32768.
+ * So, for an call with a local call number of 20000, every incoming audio
+ * frame would require 20000 mutex lock and unlock operations. Ouch.
+ *
+ * It's a shame that IAX2 media frames carry the source call number instead of
+ * the destination call number. If they did, this lookup wouldn't be needed.
+ * However, it's too late to change that now. Instead, we need to come up with
+ * a better way of indexing active calls so that these frequent lookups are not
+ * so expensive.
+ */
static int find_callno(unsigned short callno, unsigned short dcallno, struct sockaddr_in *sin, int new, int lockpeer, int sockfd)
{
int res = 0;
--
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