Re: linux-next network throughput performance regression

On Sun, Nov 8, 2015 at 7:31 PM, Dexuan Cui [off-list ref] wrote:

quoted

From: David Miller [mailto:davem@davemloft.net]
Sent: Monday, November 9, 2015 11:24
...

quoted

Thanks, David!
I understand 1 TX queue is the bottleneck (however in Simon's
test, TX=1 => 36.7Gb/s, TX=8 => 37.7 Gb/s, so it looks the TX=1 bottleneck
is not so obvious).
I'm just wondering how the bottleneck became much narrower with
recent linux-next in Simon's result (36.7 Gb/s vs. 18.2 Gb/s). IMO there
must be some latency somewhere.

I think the whole thing here is that you misinterpreted what Eric said.

He is not arguing that some regression did, or did not, happen.

He instead was making the basic statement about the fact that due to
the lack of paralellness a single stream TCP case is harder to
optimize for high speed NICs.

That is all.

Thanks, I got it.
I'm actually new to network performance tuning, trying to understand
all the related details. :-)

You might want to look at
https://www.kernel.org/doc/Documentation/networking/scaling.txt as an
introduction to the scaling capabilities of the stack.

Tom

Thanks,
-- Dexuan
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html