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Re: Memory consumption in tshark
From: Joerg Mayer <jmayer () loplof de>
Date: Tue, 27 Aug 2013 23:24:17 +0200

On Tue, Aug 27, 2013 at 05:09:19PM -0400, Evan Huus wrote:
IIRC, two-pass allows for most/all of the reassembly/request-response
stuff,
which we want to do sometimes. Any ideas why we have to keep some
information
indefinitely?


Two-pass requires us to keep *all* the state around through the first pass
so that it is available during the second pass (at which point it can be
discarded).  Even in single-pass mode, there is some state that we can't
always immediately discard. If I see a fragment of a TCP message then it
doesn't make sense to discard that until the other fragments have arrived
and been reassembled. If I see a request, I probably need to keep state
from that request until the response (which may never show up).

We already do reassembly and a lot of other stateful work in single-pass
mode. The only thing two-pass mode provides is the ability to "see the
future" (for example, saying: this request has a response 5 packets later).

So (assuming we really free everything we could already) could add a
possibly configurable foresight horizon of 10000 packets. If a packet
number is older than 10000 packets, forget it?

Ciao
        Jörg

-- 
Joerg Mayer                                           <jmayer () loplof de>
We are stuck with technology when what we really want is just stuff that
works. Some say that should read Microsoft instead of technology.
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