Subject: Re: [Xen-devel] "tcp: refine TSO autosizing" causes performance regression on Xen

From: Rick Jones <[email-masked]>
Date: Wed, 15 Apr 2015 11:19:15 -0700

On 04/15/2015 11:08 AM, Eric Dumazet wrote:
> On Wed, 2015-04-15 at 10:55 -0700, Rick Jones wrote:
>>>
>>> Have you tested this patch on a NIC without GSO/TSO ?
>>>
>>> This would allow more than 500 packets for a single flow.
>>>
>>> Hello bufferbloat.
>>
>> Woudln't the fq_codel qdisc on that interface address that problem?
>
> Last time I checked, default qdisc was pfifo_fast.

Bummer.

> These guys do not want to change a sysctl, how pfifo_fast will magically
> becomes fq_codel ?

Well, I'm not sure that it is George and Jonathan themselves who don't 
want to change a sysctl, but the customers who would have to tweak that 
in their VMs?

rick