Andi Kleen wrote:
On Wednesday 30 January 2008 20:22, Ben Greear wrote:
We use these features to enable creating very high numbers of short-lived
TCP connections, primarily used as a test tool for other network
devices.
Hopefully these other network devices don't do any NAT then
or don't otherwise violate the IP-matches-PAWS assumption.
Most likely they do actually, so enabling TW recycle
for testing is probably not even safe for you.
Modern systems have a lot of RAM so even without tw recycle
you should be able to get a very high number of connections.
An timewait socket is around 128 bytes on 64bit; this means
with a GB of memory you can already support > 8 Million TW sockets.
On 32bit it's even more.
I believe the problem was that all of my ports were used up with
TIME_WAIT sockets and so it couldn't create more. My test
case was similar to this:
1 Have one machine B listen for connections on one interface (one IP).
2 Have one machine A make a connection to B, and close connection
immediately or soon after
it was established.
goto 2
The goal was to make a maximum number of TCP connections per second.
The data passed
is just filler, and for the fastest settings, we don't pass data at all.
Without setting
tcp_tw_recycle to 1, the system could do only a few thousand connections
per second. With
it set to 1, I think I was getting around 10,000. Either way, it was
significantly faster than
w/out recycle enabled.
So, is there a better way to max out the connections per second without
having to use tcp_tw_recycle?
Thanks,
Ben
--
Ben Greear <[EMAIL PROTECTED]>
Candela Technologies Inc http://www.candelatech.com
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