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- Fixed mistakes in latency and xmitBytes calculation math

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which lead to ineffective multilink packet distribution plans.
- Changed bytesInQueue calculation math to have more precise information
about links utilization.
- Taken rough account of the link overhead. Better way to do it could be to
get exact overhead from user-level, but I have not done it to keep
binary compatibility.

Reviewed by:	archie
Approved by:	glebius (mentor)
This commit is contained in:
Alexander Motin 2007-04-20 08:22:57 +00:00
parent cd4cf11a4d
commit fd58342c26
1 changed files with 22 additions and 6 deletions
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28
sys/netgraph/ng_ppp.c
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@ -177,6 +177,9 @@ MALLOC_DEFINE(M_NETGRAPH_PPP, "netgraph_ppp", "netgraph ppp node");
/* Fragment queue scanner period */
#define MP_FRAGTIMER_INTERVAL (hz/2)
/* Average link overhead. XXX: Should be given by user-level */
#define MP_AVERAGE_LINK_OVERHEAD 16
/* Keep this equal to ng_ppp_hook_names lower! */
#define HOOK_INDEX_MAX 13
@ -1289,8 +1292,14 @@ ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
/* bytesInQueue and lastWrite required only for mp_strategy. */
if (priv->conf.enableMultilink && !priv->allLinksEqual) {
link->bytesInQueue += len;
getmicrouptime(&link->lastWrite);
/* If queue was empty, then mark this time. */
if (link->bytesInQueue == 0)
getmicrouptime(&link->lastWrite);
link->bytesInQueue += len + MP_AVERAGE_LINK_OVERHEAD;
/* Limit max queue length to 50 pkts. BW can be defined
incorrectly and link may not signal overload. */
if (link->bytesInQueue > 50 * 1600)
link->bytesInQueue = 50 * 1600;
}
}
return (error);
@ -2103,13 +2112,17 @@ ng_ppp_mp_strategy(node_p node, int len, int *distrib)
/* Compute time delta since last write */
diff = now;
timevalsub(&diff, &alink->lastWrite);
/* alink->bytesInQueue will be changed, mark change time. */
alink->lastWrite = now;
if (now.tv_sec < 0 || diff.tv_sec >= 10) { /* sanity */
alink->bytesInQueue = 0;
continue;
}
/* How many bytes could have transmitted since last write? */
xmitBytes = (alink->conf.bandwidth * diff.tv_sec)
xmitBytes = (alink->conf.bandwidth * 10 * diff.tv_sec)
+ (alink->conf.bandwidth * (diff.tv_usec / 1000)) / 100;
alink->bytesInQueue -= xmitBytes;
if (alink->bytesInQueue < 0)
@ -2290,13 +2303,16 @@ ng_ppp_update(node_p node, int newConf)
for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
int hdrBytes;
hdrBytes = (priv->links[i].conf.enableACFComp ? 0 : 2)
if (priv->links[i].conf.bandwidth == 0)
continue;
hdrBytes = MP_AVERAGE_LINK_OVERHEAD
+ (priv->links[i].conf.enableACFComp ? 0 : 2)
+ (priv->links[i].conf.enableProtoComp ? 1 : 2)
+ (priv->conf.xmitShortSeq ? 2 : 4);
priv->links[i].latency =
priv->links[i].conf.latency +
((hdrBytes * priv->links[i].conf.bandwidth) + 50)
/ 100;
(hdrBytes / priv->links[i].conf.bandwidth + 50) / 100;
}
}