Dummynet low bandwidth simulation

Ivan Voras ivoras at fer.hr
Tue Apr 27 05:08:37 PDT 2004

Luigi Rizzo wrote:

> considering your msg about rst etc -- there are a number of potential
> failure modes including the most likely one below:
>  + because of the extra delay, the initial syn handshake takes too
>    long to complete causing way too many entries in the listen queue,
>    so this saturates the server side.

I dont' understand this - the messages ("limiting RST response freq.") are 
not showing on the server side (where the web server is), but on the client.

(Apache's default backlog is 511 and I raised kern.ipc.somaxconn to 1000 on 
the server).

But I've discovered a possible cause: apache httpd processes have been 
dyeing on the server, and occasionally I see: "collecting pv entries, 
suggest increasing PMAP_SHPGPERPROC". What is that?

Every sufficiently advanced magic is indistinguishable from technology
    - Arthur C Anticlarke

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