[dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to the TX path

[Xu, Qian Q]

In my BDW-EP platform(similar to HSW), I can also see the performance drop. So what's the next step now? 
Intel CPU GEN: 
SNB-->IVB--->HSW-->BDW-EP

-----Original Message-----
From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Maxime Coquelin
Sent: Thursday, October 27, 2016 6:53 PM
To: Yuanhan Liu <yuanhan.liu at linux.intel.com>
Cc: mst at redhat.com; dev at dpdk.org; vkaplans at redhat.com
Subject: Re: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to the TX path



On 10/27/2016 12:33 PM, Yuanhan Liu wrote:
> On Thu, Oct 27, 2016 at 11:10:34AM +0200, Maxime Coquelin wrote:
>> Hi Zhihong,
>>
>> On 10/27/2016 11:00 AM, Wang, Zhihong wrote:
>>> Hi Maxime,
>>>
>>> Seems indirect desc feature is causing serious performance 
>>> degradation on Haswell platform, about 20% drop for both mrg=on and 
>>> mrg=off (--txqflags=0xf00, non-vector version), both iofwd and 
>>> macfwd.
>> I tested PVP (with macswap on guest) and Txonly/Rxonly on an Ivy 
>> Bridge platform, and didn't faced such a drop.
>
> I was actually wondering that may be the cause. I tested it with my 
> IvyBridge server as well, I saw no drop.
Sorry, mine is a SandyBridge, not IvyBridge.