Re: Weird network performance problem

[Greg Troxel <gdt%lexort.com@localhost>]

Chavdar Ivanov <ci4ic4%gmail.com@localhost> writes:

> From what I can see, the reason is
>
> sysctl -w net.inet.tcp.{send|recv}space=131072
>
> If I revert to 32768, I get back about the third of the speed.

That is odd.  It seems like the sender is not doing well if the window
is bigger.  But, that could mean that queues in your switches are being
overrun.   Until you look at the packet-level loss and retransmission
behavior you really can't tell what is going on.

> net.inet.tcp.{send|recv}buf_auto doesn't seem to make any difference.

I am unclear, but it may be that auto is about making adjustments from
the default, so that could make sense.