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authorgdt <gdt>2005-02-15 18:10:03 +0100
committergdt <gdt>2005-02-15 18:10:03 +0100
commit6ea7cdc593f7637e26da54192ef67245185994f3 (patch)
treea4b5e80d3936a582d503750408395039ff273848 /bgpd/IMPLEMENTATION.txt
parent2005-02-15 Paul Jakma <paul.jakma@sun.com> (diff)
downloadfrr-6ea7cdc593f7637e26da54192ef67245185994f3.tar.xz
frr-6ea7cdc593f7637e26da54192ef67245185994f3.zip
Adjust size complexity estimates. Still not quite right, but closer.
Diffstat (limited to 'bgpd/IMPLEMENTATION.txt')
-rw-r--r--bgpd/IMPLEMENTATION.txt18
1 files changed, 13 insertions, 5 deletions
diff --git a/bgpd/IMPLEMENTATION.txt b/bgpd/IMPLEMENTATION.txt
index d0b270b45..fff360ab9 100644
--- a/bgpd/IMPLEMENTATION.txt
+++ b/bgpd/IMPLEMENTATION.txt
@@ -1,4 +1,4 @@
-$Id: IMPLEMENTATION.txt,v 1.1 2005/02/10 16:38:09 gdt Exp $
+$Id: IMPLEMENTATION.txt,v 1.2 2005/02/15 17:10:03 gdt Exp $
This file contains notes about the internals of the BGP
implementation. The initial impetus is understanding the memory usage
@@ -150,10 +150,18 @@ bgpd.c
Question: How much memory does quagga's bgpd use as a function of
state received from peers?
-It seems that a struct bgp_info is kept for each prefix, and this has
-its own struct attr. aspath, etc. are 'interned' and shared.
-So, it seems that 144 bytes are used per received prefix, plus storage
-for all unique aspaths received.
+It seems that a struct bgp_info is kept for each prefix. The "struct
+attr *" is interned, and variables within that are interned. So, 40
+bytes are kept per received prefix, plus interned shared values. This
+could be 36 if 'int suppress' where changed to a u_char and moved to
+be with the other u_chars. Without MPLS, this could be 32 bytes.
+Note that 8 bytes of this is linked list overhead, meaning that 24
+bytes are the raw per-prefix storage requirements.
+
+Also, a struct bgp_damp_info is apparently maintained per route; this
+is fairly large (about 44 bytes).
+
+[TODO: the role of struct bgp_node.]
* TIME COMPLEXITY