Updating our TCP and socket sysctl values...

Jeff Roberson jroberson at jroberson.net
Sat Mar 19 22:21:30 UTC 2011

On Sat, 19 Mar 2011, Alexander Leidinger wrote:

> On Sat, 19 Mar 2011 15:37:47 +0900 George Neville-Neil
> <gnn at neville-neil.com> wrote:
>> Hash: SHA1
>> 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/

Are they not talking about buffers in non-endpoint devices?  Or perhaps 
even overly large rx queues in endpoints, but not local socket receive 
buffers?  It seems that they are describing situations where excessive 
buffering masks network conditions until it's too late.


> Bye,
> Alexander.
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