CCID-4 Kconfig and Makefile

[CCID-4] CCID-4 Kconfig and Makefile

Index: leandro.new/net/dccp/ccids/Kconfig =================================--- leandro.new.orig/net/dccp/ccids/Kconfig +++ leandro.new/net/dccp/ccids/Kconfig
@@ -106,9 +106,82 @@ config IP_DCCP_CCID3_RTO
is serious network congestion: experimenting with larger values should therefore not be performed on WANs.

-# The TFRC Library: currently only has CCID 3 as customer +config IP_DCCP_CCID4

+       tristate "CCID4 (TCP-Friendly, Small Packet Variant) (EXPERIMENTAL)"
+       depends on IP_DCCP
+       def_tristate IP_DCCP
+       ---help---
+          CCID-4 denotes Congestion Control Identifier 4, the Small-Packet
+          variant of TCP-Friendly Rate Control (TFRC), in the Datagram
+          Congestion Control Protocol (DCCP).  CCID 4 is for experimental use,
+          and uses TFRC-SP [RFC4828], a variant of TFRC designed for applications
+          that send small packets.  The goal for TFRC-SP is to achieve roughly the
+          same bandwidth in bits per second (bps) as a TCP flow using packets of up
+          to 1500 bytes but experiencing the same level of congestion.  CCID 4 is for
+          experimental use for senders that send small packets and would like a
+          TCP-friendly sending rate, possibly with Explicit Congestion
+          Notification (ECN), while minimizing abrupt rate changes.

+
+ CCID-4 is a Internet-Draft and it can be found at:
+ https://datatracker.ietf.org/drafts/draft-floyd-dccp-ccid4/
+
+ The TFRC-SP congestion control algorithms were initially described in
+ RFC 4828.
+
+ To compile this CCID as a module, choose M here: the module will be
+ called dccp_ccid4.
+
+ If in doubt, say M.
+
+config IP_DCCP_CCID4_DEBUG

+         bool "CCID4 debugging messages"
+         depends on IP_DCCP_CCID4
+         ---help---
+           Enable CCID4-specific debugging messages.
+
+           When compiling CCID4 as a module, this debugging output can
+           additionally be toggled by setting the ccid4_debug module
+           parameter to 0 or 1.

+
+ If in doubt, say N.
+
+config IP_DCCP_CCID4_RTO

+         int "Use higher bound for nofeedback timer"
+         default 100
+         depends on IP_DCCP_CCID4 && EXPERIMENTAL
+         ---help---

+ This help is a copy of CCID3 RTO option. It must be updated, if
+ necessary, according to the CCID-4 internet draft.
+
+ Use higher lower bound for nofeedback timer expiration.
+

+           The TFRC-SP nofeedback timer normally expires after the maximum of 4
+           RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
+           with a small RTT this can mean a high processing load and reduced
+           performance, since then the nofeedback timer is triggered very
+           frequently.

+
+ This option enables to set a higher lower bound for the nofeedback
+ value. Values in units of milliseconds can be set here.
+

+           A value of 0 disables this feature by enforcing the value specified
+           in RFC 3448. The following values have been suggested as bounds for
+           experimental use:
+               * 16-20ms to match the typical multimedia inter-frame interval
+               * 100ms as a reasonable compromise [default]
+               * 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
+
+           The default of 100ms is a compromise between a large value for
+           efficient DCCP implementations, and a small value to avoid disrupting
+           the network in times of congestion.
+
+           The purpose of the nofeedback timer is to slow DCCP down when there
+           is serious network congestion: experimenting with larger values should
+           therefore not be performed on WANs.

+
+# The TFRC Library: currently has CCID 3 and CCID 4 as customer
config IP_DCCP_TFRC_LIB
- depends on IP_DCCP_CCID3
+ depends on IP_DCCP_CCID3 || IP_DCCP_CCID4
def_tristate IP_DCCP_CCID3

config IP_DCCP_TFRC_DEBUG
Index: leandro.new/net/dccp/ccids/Makefile =================================--- leandro.new.orig/net/dccp/ccids/Makefile +++ leandro.new/net/dccp/ccids/Makefile
@@ -1,3 +1,7 @@
+obj-$(CONFIG_IP_DCCP_CCID4) += dccp_ccid4.o
+
+dccp_ccid4-y := ccid4.o
+
obj-$(CONFIG_IP_DCCP_CCID3) += dccp_ccid3.o

dccp_ccid3-y := ccid3.o

| +config IP_DCCP_CCID4_DEBUG
| +         bool "CCID4 debugging messages"
| +         depends on IP_DCCP_CCID4
<snip>
| +# The TFRC Library: currently has CCID 3 and CCID 4 as customer
|  config IP_DCCP_TFRC_LIB
| -	depends on IP_DCCP_CCID3
| +	depends on IP_DCCP_CCID3 || IP_DCCP_CCID4
|  	def_tristate IP_DCCP_CCID3
|  
|  config IP_DCCP_TFRC_DEBUG

Suggestion: if CCID3 is not compiled as module, there will currently be no TFRC debugging output for dccp_tfrc_lib when only CCID4 is enabled. Something like

config IP_DCCP_TFRC_DEBUG

	bool
	default y if IP_DCCP_CCID3_DEBUG || IP_DCCP_CCID4_DEBUG 

would enable this.

On the other hand, the number of `debugs' keeps continually growing. Maybe it is possible to just use tfrc_debug for everything that speaks TFRC, otherwise we currently have
* tfrc_debug to enable debug messages in dccp_tfrc_lib

 * ccid3_debug            "                 dccp_ccid3
 * ccid4_debug            "                 dccp_ccid4

* dccp_debug to see the rest

2007/11/8, Gerrit Renker <[email protected]>:

Yes, it is better to have tfrc_debug for everything related to TFRC. I will also fix the IP_DCCP_TFRC_DEBUG kconfig option like you suggested.

Leandro.

Quoting Leandro:

| 2007/11/8, Gerrit Renker <[email protected]>:
| > | +config IP_DCCP_CCID4_DEBUG
| > | +         bool "CCID4 debugging messages"
| > | +         depends on IP_DCCP_CCID4
| > <snip>
| > | +# The TFRC Library: currently has CCID 3 and CCID 4 as customer
| > |  config IP_DCCP_TFRC_LIB
| > | -     depends on IP_DCCP_CCID3
| > | +     depends on IP_DCCP_CCID3 || IP_DCCP_CCID4
| > |       def_tristate IP_DCCP_CCID3
| > |
| > |  config IP_DCCP_TFRC_DEBUG
| > Suggestion: if CCID3 is not compiled as module, there will currently be
| > no TFRC debugging output for dccp_tfrc_lib when only CCID4 is enabled.
| > Something like
| >
| > config IP_DCCP_TFRC_DEBUG
| >         bool
| >         default y if IP_DCCP_CCID3_DEBUG || IP_DCCP_CCID4_DEBUG
| >
| > would enable this.
| >
| > On the other hand, the number of `debugs' keeps continually growing.
| > Maybe it is possible to just use tfrc_debug for everything that speaks
| > TFRC, otherwise we currently have
| >  * tfrc_debug   to enable debug messages in dccp_tfrc_lib
| >  * ccid3_debug            "                 dccp_ccid3
| >  * ccid4_debug            "                 dccp_ccid4
| >  * dccp_debug   to see the rest
| > -
| 
| Yes, it is better to have tfrc_debug for everything related to TFRC. I
| will also fix the IP_DCCP_TFRC_DEBUG kconfig option like you
| suggested.
| 

Please do as you see fit, but don't worry too much at this stage - this can all be resolved later (i.e. further abstraction can be done later).

2007/11/13, Gerrit Renker <[email protected]>:

Then I will let this as it is and after we can working on this. Ok?

| > | > Suggestion: if CCID3 is not compiled as module, there will currently be
| > | > no TFRC debugging output for dccp_tfrc_lib when only CCID4 is enabled.
| > | > Something like
| > | >
| > | > config IP_DCCP_TFRC_DEBUG
| > | >         bool
| > | >         default y if IP_DCCP_CCID3_DEBUG || IP_DCCP_CCID4_DEBUG
| > | >
| > | > would enable this.
| > | >
| > | > On the other hand, the number of `debugs' keeps continually growing.
| > | > Maybe it is possible to just use tfrc_debug for everything that speaks
| > | > TFRC, otherwise we currently have
| > | >  * tfrc_debug   to enable debug messages in dccp_tfrc_lib
| > | >  * ccid3_debug            "                 dccp_ccid3
| > | >  * ccid4_debug            "                 dccp_ccid4
| > | >  * dccp_debug   to see the rest
| > | > -
<snip>
| 
| Then I will let this as it is and after we can working on this. Ok?
| 

Yes that's absolutely fine. I just checked: none of the trees (origin|dccp|ccid4) currently uses tfrc_pr_debug(), so this is something to be investigated when thinking of sharing code between ccid4/ccid3.

Either that macro / variable should then be obsoleted, or it could be shared between CCID3/4.