Subject: Socket send-buffer auto-sizing

From: Ben Greear <[email-masked]>
Date: Thu, 07 Jun 2012 10:59:29 -0700

I'm continuing to test one-way tcp streams in 3.5.0-rc1 on
a wifi network.

When I do not specify a send buffer size, and thus use the kernel
defaults, max speed is about 77Mbps.

When I specify 512KB send-buffer, I get speeds up to 185Mbps.

When set to 1MB, I get about 198Mbps (and setting higher does not
increase the throughput after this).

This is without any 'delack' patches applied.

My question is:  Should the kernel auto-tuner work better?

I seem to recall a comments from some years ago that applications
should no longer attempt to tune send/recv buffers because the kernel
was smart enough to get it at least mostly right.

Thanks,
Ben

-- 
Ben Greear <[email-masked]>
Candela Technologies Inc  http://www.candelatech.com