Updating our TCP and socket sysctl values...

[George Neville-Neil]

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On Mar 20, 2011, at 00:04 , Alexander Leidinger wrote:

> On Sat, 19 Mar 2011 15:37:47 +0900 George Neville-Neil
> <gnn at neville-neil.com> wrote:
> 
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>> Howdy,
>> 
>> I believe it's time for us to upgrade our sysctl values for TCP
>> sockets so that they are more in line with the modern world.  At the
>> moment we have these limits on our buffering:
>> 
>> kern.ipc.maxsockbuf: 262144
>> net.inet.tcp.recvbuf_max: 262144
>> net.inet.tcp.sendbuf_max: 262144
>> 
>> I believe it's time to up these values to something that's in line
>> with higher speed local networks, such as 10G.  Perhaps it's time to
>> move these to 2MB instead of 256K.
>> 
>> Thoughts?
> 
> I suggest to read
>  http://www.bufferbloat.net/projects/bloat/wiki/Bufferbloat
> and do a before/after test to make sure we do not suffer from the
> described problem. Jim Getty has test descriptions:
>  http://gettys.wordpress.com/category/bufferbloat/
> 

No need to read those, I heard him talk about it at dinner a
few weeks ago.  What he's mostly talking about is buffer bloat
in non endpoint devices.  Note that I'm not talking about changing
where we start, but what the maximum is.  It is definitely the
case, and Jeff Roberson can back me up on this, that our defaults
are hampering the out of the box experience for our users.

Best,
George


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