Talk:Locality-Based Least-Connection Scheduling - Revision history

Jkrzyszt: /* Expiration algorithm */

2006-09-23T17:50:38Z

‎Expiration algorithm

Wensong at 13:43, 23 September 2006

2006-09-23T13:43:36Z

Jkrzyszt: /* Expiration algorithm */

2006-09-19T14:48:21Z

‎Expiration algorithm

Jkrzyszt: /* Expiration algorithm */

2006-09-18T14:20:09Z

‎Expiration algorithm

Jkrzyszt at 18:31, 15 September 2006

2006-09-15T18:31:45Z

New page

==Expiration algorithm==
I find it usefull for understanding why subsequent connections to the same destination IP address may not follow the same path.
ServerNode[] is a list of maps from destination IP address to server;
C(ServerNode[]) is the current number of not NULL maps in the list;
Now is the current system time;
net.ipv4.vs.lblc_expiration is the sysctl parameter (default 24 hours).
Every 1 minute:
Count = C(ServerNode[]);
if (Count > 16384) then {
for (dest_ip = 0.0.0.0;
C(ServerNode[]) > min((Count-16384)*4/3, 8192);
dest_ip++) {
if (ServerNode[dest_ip].server is not NULL AND
ServerNode[dest_ip].lastuse < Now - 6 minutes) then
ServerNode[dest_ip].server = NULL;
}
}
Every 30 minutes:
for (dest_ip = 0.0.0.0; dest_ip < 255.255.255.255; dest_ip++) {
if (ServerNode[dest_ip].server is not NULL AND
ServerNode[dest_ip].lastuse < Now - net.ipv4.vs.lblc_expiration) then
ServerNode[dest_ip].server = NULL;
}
Please correct me if I am wrong.
:[[User:Jkrzyszt|Jkrzyszt]] 02:31, 16 September 2006 (CST)

← Older revision		Revision as of 17:50, 23 September 2006
Line 95:		Line 95:

	: Thanks a lot for the patch, I'll try to include it in the mainstream kernel. --[[User:Wensong\|Wensong]] 21:43, 23 September 2006 (CST)		: Thanks a lot for the patch, I'll try to include it in the mainstream kernel. --[[User:Wensong\|Wensong]] 21:43, 23 September 2006 (CST)
		+	-----
		+	Fine. For your convenience, the raw patch is available [http://www.icnet.pl/download/ip_vs_lblc-timeout.patch here].
		+	:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 01:50, 24 September 2006 (CST)

← Older revision		Revision as of 13:43, 23 September 2006
Line 93:		Line 93:
	Are there any chances for this modification to be included in the mainstream kernel?		Are there any chances for this modification to be included in the mainstream kernel?
	:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 22:48, 19 September 2006 (CST)		:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 22:48, 19 September 2006 (CST)
		+
		+	: Thanks a lot for the patch, I'll try to include it in the mainstream kernel. --[[User:Wensong\|Wensong]] 21:43, 23 September 2006 (CST)

← Older revision		Revision as of 14:48, 19 September 2006
Line 44:		Line 44:

	:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 22:20, 18 September 2006 (CST)		:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 22:20, 18 September 2006 (CST)
		+	-----
		+	I found it much simpler to expose an additional sysctl variable
		+	and use it in place of the hardcoded ENTRY_TIMEOUT parameter.
		+	--- linux-source-2.6.15/include/net/ip_vs.h 2006-01-03 04:21:10.000000000 +0100
		+	+++ linux-source-2.6.15-1-e50-debug_7bpo1.200604270947/include/net/ip_vs.h 2006-09-19 15:29:01.000000000 +0200
		+	@@ -359,6 +359,7 @@
		+	NET_IPV4_VS_SYNC_THRESHOLD=24,
		+	NET_IPV4_VS_NAT_ICMP_SEND=25,
		+	NET_IPV4_VS_EXPIRE_QUIESCENT_TEMPLATE=26,
		+	+ NET_IPV4_VS_LBLC_TIMEOUT=27,
		+	NET_IPV4_VS_LAST
		+	};
		+	--- linux-source-2.6.15/net/ipv4/ipvs/ip_vs_lblc.c 2006-01-03 04:21:10.000000000 +0100
		+	+++ linux-source-2.6.15-1-e50-debug_7bpo1.200604270947/net/ipv4/ipvs/ip_vs_lblc.c 2006-09-19 16:37:29.000000000 +0200
		+	@@ -57,6 +57,7 @@
		+	*/
		+	#define CHECK_EXPIRE_INTERVAL (60*HZ)
		+	#define ENTRY_TIMEOUT (660HZ)
		+	+static int sysctl_ip_vs_lblc_timeout = ENTRY_TIMEOUT;
		+
		+	/*
		+	* It is for full expiration check.
		+	@@ -118,6 +119,14 @@
		+	.mode = 0644,
		+	.proc_handler = &proc_dointvec_jiffies,
		+	},
		+	+ {
		+	+ .ctl_name = NET_IPV4_VS_LBLC_TIMEOUT,
		+	+ .procname = "lblc_timeout",
		+	+ .data = &sysctl_ip_vs_lblc_timeout,
		+	+ .maxlen = sizeof(int),
		+	+ .mode = 0644,
		+	+ .proc_handler = &proc_dointvec_jiffies,
		+	+ },
		+	{ .ctl_name = 0 }
		+	};
		+
		+	@@ -367,7 +376,7 @@
		+
		+	write_lock(&tbl->lock);
		+	list_for_each_entry_safe(en, nxt, &tbl->bucket[j], list) {
		+	- if (time_before(now, en->lastuse + ENTRY_TIMEOUT))
		+	+ if (time_before(now, en->lastuse + sysctl_ip_vs_lblc_timeout))
		+	continue;
		+
		+	ip_vs_lblc_free(en);
		+	Now I can tune the every minute expiration procedure to suit my needs.
		+	Are there any chances for this modification to be included in the mainstream kernel?
		+	:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 22:48, 19 September 2006 (CST)

← Older revision		Revision as of 14:20, 18 September 2006
Line 24:		Line 24:
	Please correct me if I am wrong.		Please correct me if I am wrong.
	:[[User:Jkrzyszt\|Jkrzyszt]] 02:31, 16 September 2006 (CST)		:[[User:Jkrzyszt\|Jkrzyszt]] 02:31, 16 September 2006 (CST)
		+	--------
		+	When I started to use the lblc algorithm I found that it provides an extra feature
		+	- some kind of connection persistance.
		+	However, the expiration algorithm, as it is, does not take into account
		+	if the destination map just to be removed is related to any active connections.
		+	This way, connection persistance is not guaranteed, even with very high weights set.
		+
		+	You may ask why not to use the persistance option.
		+	Well, the lblc algorithm is designed to be used together with fwmark in transparent cache clusters.
		+	If such a cluster is accessed through another proxy (that applies access control rules, for example),
		+	using classical persistance solution is not an option
		+	because all the traffic from this proxy would be directed to the same cache.
		+
		+	I am going to investigate the sources if it would be possible to check for no active
		+	(or maybe even inactive) conections using the specific map before it can be removed
		+	from the list.
		+
		+	I would appreciate any comments on this matter.
		+
		+	:Janusz [[User:Jkrzyszt\|Jkrzyszt]] 22:20, 18 September 2006 (CST)