[asterisk-commits] russell: trunk r56447 -
/trunk/channels/chan_iax2.c
asterisk-commits at lists.digium.com
asterisk-commits at lists.digium.com
Fri Feb 23 14:20:34 MST 2007
Author: russell
Date: Fri Feb 23 15:20:33 2007
New Revision: 56447
URL: http://svn.digium.com/view/asterisk?view=rev&rev=56447
Log:
Merge team/russell/iax2_performance.
There is not a large amount of code here and the changes are not very invasive.
However, they should significantly improve performance of chan_iax2 under load.
IAX2 media frames only carry the *source* call number. So, when one arrives,
the correct session that it is a part of has to be matched on IP address, port
number, and call number, instead of just a call number. Had these frames
carried the *destination* call number, this would not be an issue, because that
would be a unique identifier that would make it easy to immediately identify
the correct session.
The way that chan_iax2 did this matching was extremely inefficient. It starts
at the first available call number and traverses each call number sequentially,
locking and unlocking a mutex for each one, to try to match against it. It
would do this regardless of whether the call number was in use or not. So,
for a call with a local call number of 25000, every single incoming media
frame would require a traversal that required 25000 mutex lock and unlock
operations. (Note that the max call number is about 32k).
I have introduced a hash table of active IAX2 calls to improve this lookup
process. The hash is done on the IP address, port number, and call number.
So, for the previous example, a few lock/unlock operations may be done versus
25000 for each frame.
Modified:
trunk/channels/chan_iax2.c
Modified: trunk/channels/chan_iax2.c
URL: http://svn.digium.com/view/asterisk/trunk/channels/chan_iax2.c?view=diff&rev=56447&r1=56446&r2=56447
==============================================================================
--- trunk/channels/chan_iax2.c (original)
+++ trunk/channels/chan_iax2.c Fri Feb 23 15:20:33 2007
@@ -631,7 +631,14 @@
int frames_dropped;
/*! received frame count: (just for stats) */
int frames_received;
+
+ AST_LIST_ENTRY(chan_iax2_pvt) entry;
+ unsigned int hash;
};
+
+/* Somewhat arbitrary prime number */
+#define PVT_HASH_SIZE 563
+static AST_RWLIST_HEAD(pvt_list, chan_iax2_pvt) pvt_hash_tbl[PVT_HASH_SIZE];
static AST_LIST_HEAD_STATIC(queue, iax_frame);
@@ -1258,20 +1265,32 @@
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 inline unsigned int peer_hash_val(const struct sockaddr_in *sin, unsigned short callno)
+{
+ return ( (sin->sin_addr.s_addr & 0xFF000000) ^
+ (sin->sin_addr.s_addr & 0x00FF0000) ^
+ (sin->sin_addr.s_addr & 0x0000FF00) ^
+ (sin->sin_addr.s_addr & 0x000000FF) ^
+ (sin->sin_port & 0xFF00) ^ (sin->sin_port ^ 0x00FF) ^
+ (callno & 0xFF00) ^ (callno & 0x00FF) )
+ % PVT_HASH_SIZE;
+}
+
+static inline void hash_on_peer(struct chan_iax2_pvt *pvt)
+{
+ if (pvt->hash) {
+ AST_RWLIST_WRLOCK(&pvt_hash_tbl[pvt->hash]);
+ AST_RWLIST_REMOVE(&pvt_hash_tbl[pvt->hash], pvt, entry);
+ AST_RWLIST_UNLOCK(&pvt_hash_tbl[pvt->hash]);
+ }
+
+ pvt->hash = peer_hash_val(&pvt->addr, pvt->peercallno);
+
+ AST_RWLIST_WRLOCK(&pvt_hash_tbl[pvt->hash]);
+ AST_RWLIST_INSERT_HEAD(&pvt_hash_tbl[pvt->hash], pvt, entry);
+ AST_RWLIST_UNLOCK(&pvt_hash_tbl[pvt->hash]);
+}
+
static int find_callno(unsigned short callno, unsigned short dcallno, struct sockaddr_in *sin, int new, int lockpeer, int sockfd)
{
int res = 0;
@@ -1279,7 +1298,19 @@
struct timeval now;
char host[80];
if (new <= NEW_ALLOW) {
- /* Look for an existing connection first */
+ unsigned int hash = peer_hash_val(sin, callno);
+ const struct chan_iax2_pvt *pvt;
+ AST_RWLIST_RDLOCK(&pvt_hash_tbl[hash]);
+ AST_RWLIST_TRAVERSE(&pvt_hash_tbl[hash], pvt, entry) {
+ ast_mutex_lock(&iaxsl[pvt->callno]);
+ if (match(sin, callno, dcallno, iaxs[pvt->callno]))
+ res = pvt->callno;
+ ast_mutex_unlock(&iaxsl[pvt->callno]);
+ if (res > 0)
+ break;
+ }
+ AST_RWLIST_UNLOCK(&pvt_hash_tbl[hash]);
+ /* Not hashed yet, Look for an existing connection */
for (x=1;(res < 1) && (x<maxnontrunkcall);x++) {
ast_mutex_lock(&iaxsl[x]);
if (iaxs[x]) {
@@ -1326,6 +1357,7 @@
iaxs[x]->addr.sin_family = sin->sin_family;
iaxs[x]->addr.sin_addr.s_addr = sin->sin_addr.s_addr;
iaxs[x]->peercallno = callno;
+ hash_on_peer(iaxs[x]);
iaxs[x]->callno = x;
iaxs[x]->pingtime = DEFAULT_RETRY_TIME;
iaxs[x]->expiry = min_reg_expire;
@@ -1809,6 +1841,12 @@
if (!owner)
pvt->owner = NULL;
iax2_destroy_helper(pvt);
+
+ if (pvt->hash) {
+ AST_RWLIST_WRLOCK(&pvt_hash_tbl[pvt->hash]);
+ AST_RWLIST_REMOVE(&pvt_hash_tbl[pvt->hash], pvt, entry);
+ AST_RWLIST_UNLOCK(&pvt_hash_tbl[pvt->hash]);
+ }
/* Already gone */
ast_set_flag(pvt, IAX_ALREADYGONE);
@@ -5406,6 +5444,7 @@
pvt->iseqno = 0;
pvt->aseqno = 0;
pvt->peercallno = peercallno;
+ hash_on_peer(pvt);
pvt->transferring = TRANSFER_NONE;
pvt->svoiceformat = -1;
pvt->voiceformat = 0;
@@ -6616,8 +6655,12 @@
if (!inaddrcmp(&sin, &iaxs[fr->callno]->addr) && !minivid &&
f.subclass != IAX_COMMAND_TXCNT && /* for attended transfer */
- f.subclass != IAX_COMMAND_TXACC) /* for attended transfer */
+ f.subclass != IAX_COMMAND_TXACC) { /* for attended transfer */
iaxs[fr->callno]->peercallno = (unsigned short)(ntohs(mh->callno) & ~IAX_FLAG_FULL);
+ ast_mutex_unlock(&iaxsl[fr->callno]);
+ hash_on_peer(iaxs[fr->callno]);
+ ast_mutex_lock(&iaxsl[fr->callno]);
+ }
if (ntohs(mh->callno) & IAX_FLAG_FULL) {
if (option_debug && iaxdebug)
ast_log(LOG_DEBUG, "Received packet %d, (%d, %d)\n", fh->oseqno, f.frametype, f.subclass);
@@ -10103,6 +10146,9 @@
for (x = 0; x < IAX_MAX_CALLS; x++)
ast_mutex_destroy(&iaxsl[x]);
+ for (x = 0; x < PVT_HASH_SIZE; x++)
+ AST_RWLIST_HEAD_DESTROY(&pvt_hash_tbl[x]);
+
return 0;
}
@@ -10144,6 +10190,9 @@
for (x=0;x<IAX_MAX_CALLS;x++)
ast_mutex_init(&iaxsl[x]);
+ for (x = 0; x < PVT_HASH_SIZE; x++)
+ AST_RWLIST_HEAD_INIT(&pvt_hash_tbl[x]);
+
ast_cond_init(&sched_cond, NULL);
if (!(sched = sched_context_create())) {
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