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added congestion thresh parm to search alg

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This commit is contained in:
Jeff Hill
1999-07-16 16:38:59 +00:00
parent 4fb64e8933
commit 0fd2f6479b
1 changed files with 230 additions and 184 deletions
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414
src/ca/conn.c
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@@ -31,6 +31,12 @@
/* */
/*
* $Log$
* Revision 1.43.4.1 1999/07/15 20:33:46 jhill
* added congestion thresh to search sched alg
*
* Revision 1.43 1998/11/17 02:40:56 jhill
* fixed infinite loop
*
* Revision 1.42 1998/10/07 14:30:41 jba
* Modified log message.
*
@@ -253,203 +259,234 @@ void manage_conn()
ca_static->ca_manage_conn_active = FALSE;
}
/*
* retrySearchRequest ()
*/
LOCAL void retrySearchRequest ()
{
ciu chan;
ciu firstChan;
int status;
unsigned nSent=0u;
if (!piiuCast) {
return;
}
/*
* check to see if there is nothing to do here
*/
if (ellCount(&piiuCast->chidlist)==0) {
return;
}
LOCK;
/*
* increment the retry sequence number
*/
ca_static->ca_search_retry_seq_no++; /* allowed to roll over */
/*
* dynamically adjust the number of UDP frames per
* try depending how many search requests are not
* replied to
*
* This determines how many search request can be
* sent together (at the same instant in time).
*
* The variable ca_static->ca_frames_per_try
* determines the number of UDP frames to be sent
* each time that retrySearchRequest() is called.
* If this value is too high we will waste some
* network bandwidth. If it is too low we will
* use very little of the incoming UDP message
* buffer associated with the server's port and
* will therefore take longer to connect. We
* initialize ca_static->ca_frames_per_try
* to a prime number so that it is less likely that the
* same channel is in the last UDP frame
* sent every time that this is called (and
* potentially discarded by a CA server with
* a small UDP input queue).
*/
/*
* increase rapidly if we see better than a 75% success rate
*/
if (ca_static->ca_search_responses >
(ca_static->ca_search_tries-(ca_static->ca_search_tries/4u)) ) {
/*
* double UDP frames per try if we have a good score
*/
if (ca_static->ca_frames_per_try < (UINT_MAX/4u) ) {
ca_static->ca_frames_per_try += ca_static->ca_frames_per_try;
#ifdef DEBUG
printf ("Increasing frame count to %u t=%u r=%u\n",
ca_static->ca_frames_per_try, ca_static->ca_search_tries,
ca_static->ca_search_responses);
ciu chan;
ciu firstChan;
int status;
unsigned nSent=0u;
if (!piiuCast) {
return;
}
/*
* check to see if there is nothing to do here
*/
if (ellCount(&piiuCast->chidlist)==0) {
return;
}
LOCK;
/*
* increment the retry sequence number
*/
ca_static->ca_search_retry_seq_no++; /* allowed to roll over */
/*
* dynamically adjust the number of UDP frames per
* try depending how many search requests are not
* replied to
*
* This determines how many search request can be
* sent together (at the same instant in time).
*
* The variable ca_static->ca_frames_per_try
* determines the number of UDP frames to be sent
* each time that retrySearchRequest() is called.
* If this value is too high we will waste some
* network bandwidth. If it is too low we will
* use very little of the incoming UDP message
* buffer associated with the server's port and
* will therefore take longer to connect. We
* initialize ca_static->ca_frames_per_try
* to a prime number so that it is less likely that the
* same channel is in the last UDP frame
* sent every time that this is called (and
* potentially discarded by a CA server with
* a small UDP input queue).
*/
/*
* increase frames per try only if we see better than
* a 93.75% success rate for one pass through the list
*/
if (ca_static->ca_search_responses >
(ca_static->ca_search_tries-(ca_static->ca_search_tries/16u)) ) {
/*
* increase UDP frames per try if we have a good score
*/
if (ca_static->ca_frames_per_try < MAXTRIESPERFRAME) {
/*
* it was observed that doubling the number of frames here infuenced
* an mbuf starvation lock up bug to occur in vxWorks 5.3.1 under
* heavy load testing of CA connection activity (the SENS IP kernel
* was not installed)
*
* therefore a congestion avoidance threshold similar to TCP is
* now used
*/
if (ca_static->ca_frames_per_try<ca_static->ca_search_tries_congest_thresh) {
ca_static->ca_frames_per_try += ca_static->ca_frames_per_try;
}
else {
ca_static->ca_frames_per_try += (ca_static->ca_frames_per_try/8) + 1;
}
#if 0
printf ("Increasing frame count to %u t=%u r=%u\n",
ca_static->ca_frames_per_try, ca_static->ca_search_tries,
ca_static->ca_search_responses);
#endif
}
}
/*
* if we have less than a 50% success rate then reduce the count gradually
*/
else if (ca_static->ca_search_responses < (ca_static->ca_search_tries/2u) ) {
if (ca_static->ca_frames_per_try>1u) {
ca_static->ca_frames_per_try--;
#ifdef DEBUG
printf ("Decreasing frame count to %u t=%u r=%u\n",
ca_static->ca_frames_per_try, ca_static->ca_search_tries,
ca_static->ca_search_responses);
}
}
/*
* if we detect congestion because we have less than a 87.5% success
* rate then gradually reduce the frames per try
*/
else if (ca_static->ca_search_responses <
(ca_static->ca_search_tries-(ca_static->ca_search_tries/8u)) ) {
if (ca_static->ca_frames_per_try>1) {
ca_static->ca_frames_per_try--;
}
ca_static->ca_search_tries_congest_thresh =
ca_static->ca_frames_per_try/2 + 1;
#if 0
printf ("Congestion detected - set frames per try to %u t=%u r=%u\n",
ca_static->ca_frames_per_try, ca_static->ca_search_tries,
ca_static->ca_search_responses);
#endif
}
}
}
/*
* a successful search_msg() sends channel to
* the end of the list
*/
firstChan = chan = (ciu) ellFirst (&piiuCast->chidlist);
while (chan) {
ca_static->ca_min_retry =
min(ca_static->ca_min_retry, chan->retry);
/*
* clear counter when we reach the end of the list
*
* if we are making some progress then
* dont increase the delay between search
* requests
*/
if (ca_static->ca_pEndOfBCastList == chan) {
if (ca_static->ca_search_responses==0u) {
#if 0
printf ("increasing search try interval\n");
#endif
cacSetRetryInterval(ca_static->ca_min_retry+1u);
}
ca_static->ca_min_retry = UINT_MAX;
/*
* increment the retry sequence number
* (this prevents the time of the next search
* try from being set to the current time if
* we are handling a response from an old
* search message)
*/
ca_static->ca_search_retry_seq_no++; /* allowed to roll over */
/*
* so that old search tries will not update the counters
*/
ca_static->ca_seq_no_at_list_begin = ca_static->ca_search_retry_seq_no;
/*
* a successful search_msg() sends channel to
* the end of the list
*/
firstChan = chan = (ciu) ellFirst (&piiuCast->chidlist);
while (chan) {
/*
* reset the search try/response counters at the end of the list
* (sequence number) so that we dont overflow, but dont subtract
* out tries that dont have a matching response yet in case they
* are delayed
*/
if (ca_static->ca_search_tries>ca_static->ca_search_responses) {
ca_static->ca_search_tries -= ca_static->ca_search_responses;
}
else {
ca_static->ca_search_tries = 0;
}
ca_static->ca_search_responses = 0;
ca_static->ca_min_retry =
min(ca_static->ca_min_retry, chan->retry);
/*
* clear counter when we reach the end of the list
*
* if we are making some progress then
* dont increase the delay between search
* requests
*/
if (ca_static->ca_pEndOfBCastList == chan) {
if (ca_static->ca_search_responses==0u) {
cacSetRetryInterval(ca_static->ca_min_retry+1u);
}
ca_static->ca_min_retry = UINT_MAX;
/*
* increment the retry sequence number
* (this prevents the time of the next search
* try from being set to the current time if
* we are handling a response from an old
* search message)
*/
ca_static->ca_search_retry_seq_no++; /* allowed to roll over */
/*
* so that old search tries will not update the counters
*/
ca_static->ca_seq_no_at_list_begin = ca_static->ca_search_retry_seq_no;
/*
* keeps the search try/response counters in bounds
* (but keep some of the info from the previous iteration)
*/
ca_static->ca_search_responses = ca_static->ca_search_responses/16u;
ca_static->ca_search_tries = ca_static->ca_search_tries/16u;
#ifdef DEBUG
printf ("saw end of list\n");
#if 0
printf ("saw end of list\n");
#endif
}
}
/*
* this moves the channel to the end of the
* list (if successful)
*/
status = search_msg (chan, DONTREPLY);
if (status != ECA_NORMAL) {
nSent++;
if (nSent>=ca_static->ca_frames_per_try) {
break;
}
/*
* flush out the search request buffer
*/
(*piiuCast->sendBytes)(piiuCast);
/*
* try again
*/
status = search_msg (chan, DONTREPLY);
if (status != ECA_NORMAL) {
break;
}
}
chan->retrySeqNo = ca_static->ca_search_retry_seq_no;
chan = (ciu) ellFirst (&piiuCast->chidlist);
/*
* dont send any of the channels twice within one try
*/
if (chan==firstChan) {
/*
* add one to nSent because there may be
* one more partial frame to be sent
*/
nSent++;
/*
* cap ca_static->ca_frames_per_try to
* the number of frames required for all of
* the unresolved channels
*/
if (ca_static->ca_frames_per_try>nSent) {
ca_static->ca_frames_per_try = nSent;
}
break;
}
}
UNLOCK;
ca_static->ca_conn_next_retry =
cac_time_sum (
&ca_static->currentTime,
&ca_static->ca_conn_retry_delay);
LOGRETRYINTERVAL
/*
* this moves the channel to the end of the
* list (if successful)
*/
status = search_msg (chan, DONTREPLY);
if (status != ECA_NORMAL) {
nSent++;
if (nSent>=ca_static->ca_frames_per_try) {
break;
}
/*
* flush out the search request buffer
*/
(*piiuCast->sendBytes)(piiuCast);
/*
* try again
*/
status = search_msg (chan, DONTREPLY);
if (status != ECA_NORMAL) {
break;
}
}
chan->retrySeqNo = ca_static->ca_search_retry_seq_no;
chan = (ciu) ellFirst (&piiuCast->chidlist);
/*
* dont send any of the channels twice within one try
*/
if (chan==firstChan) {
/*
* add one to nSent because there may be
* one more partial frame to be sent
*/
nSent++;
/*
* cap ca_static->ca_frames_per_try to
* the number of frames required for all of
* the unresolved channels
*/
if (ca_static->ca_frames_per_try>nSent) {
ca_static->ca_frames_per_try = nSent;
}
break;
}
}
UNLOCK;
ca_static->ca_conn_next_retry =
cac_time_sum (
&ca_static->currentTime,
&ca_static->ca_conn_retry_delay);
LOGRETRYINTERVAL
#ifdef DEBUG
printf("sent %u at cur sec=%u cur usec=%u delay sec=%u delay usec = %u\n",
nSent, ca_static->currentTime.tv_sec,
ca_static->currentTime.tv_usec,
ca_static->ca_conn_retry_delay.tv_sec,
ca_static->ca_conn_retry_delay.tv_usec);
printf("sent %u at cur sec=%u cur usec=%u delay sec=%u delay usec = %u\n",
nSent, ca_static->currentTime.tv_sec,
ca_static->currentTime.tv_usec,
ca_static->ca_conn_retry_delay.tv_sec,
ca_static->ca_conn_retry_delay.tv_usec);
#endif
}
/*
@@ -630,6 +667,15 @@ void mark_server_available (const struct sockaddr_in *pnet_addr)
}
UNLOCK;
# if DEBUG
{
char buf[64];
ipAddrToA (pnet_addr, buf, sizeof(buf));
printf ("new server available: %s\n", buf);
}
# endif
}
/*