1 May
2017
1 May
'17
3:11 p.m.
I think the most efficient technique is to make the
per-address lookup
table an mmap'd array of pointers to entries in the existing route table.
That makes it effectively addrtable[2][2**24], right?
Yes. Of course a single pointer would be 8 bytes when it is compiled for 64 bits,
but it would not need to be. When your existing route table is an array
rather than a collection of malloc'ed objects linked by pointers, the
"pointer"
from the address lookup table into the route table could be the smaller index
into the route table (that would easily fit in an unsigned short integer, allowing
for 65535 gateways).
Or, in 32 bit mode a simple pointer can be used (4 bytes per entry).
Rob
1 May
1 May
3:22 p.m.
New subject: amprgw routing
The existing routing table is an array of structs. Storing the
index+1 into the into the addrs table array requires some index
arithmetic, but that is relatively cheap. Yes, u_short would
save considerable memory.
- Brian
On Mon, May 01, 2017 at 09:11:17PM +0200, Rob Janssen wrote:
Yes. Of course a single pointer would be 8 bytes when
it is compiled for 64 bits,
but it would not need to be. When your existing route table is an array
rather than a collection of malloc'ed objects linked by pointers, the
"pointer"
from the address lookup table into the route table could be the smaller index
into the route table (that would easily fit in an unsigned short integer, allowing
for 65535 gateways).
Or, in 32 bit mode a simple pointer can be used (4 bytes per entry).
6:04 p.m.
New subject: amprgw routing
Using a simple global array to be the list of addresses and pointers,
full load time went from about 3ms to 15ms. But it works just fine and
the lookups are so fast the microsecond timer registers zero.
- Brian
On Mon, May 01, 2017 at 09:11:17PM +0200, Rob Janssen wrote:
Yes. Of course a single pointer would be 8 bytes when
it is compiled for 64 bits,
but it would not need to be. When your existing route table is an array
rather than a collection of malloc'ed objects linked by pointers, the
"pointer"
from the address lookup table into the route table could be the smaller index
into the route table (that would easily fit in an unsigned short integer, allowing
for 65535 gateways).
Or, in 32 bit mode a simple pointer can be used (4 bytes per entry).
Rob
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Brian Kantor -
Rob Janssen