diff options
Diffstat (limited to 'bgpd/IMPLEMENTATION.txt')
| -rw-r--r-- | bgpd/IMPLEMENTATION.txt | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/bgpd/IMPLEMENTATION.txt b/bgpd/IMPLEMENTATION.txt index d0b270b4..fff360ab 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 |