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From: Alex Williamson <alex.williamson@redhat.com>
To: Bob Chen <a175818323@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	"Marcel Apfelbaum" <marcel@redhat.com>, 陈博 <chenbo02@meituan.com>,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] About virtio device hotplug in Q35! 【外域邮件.谨慎查阅】
Date: Wed, 30 Aug 2017 10:43:04 -0600	[thread overview]
Message-ID: <20170830104304.4a0fca34@w520.home> (raw)
In-Reply-To: <CAMxP3BRFzyyHemEW-2DFRd7r9Py-bkjY7vQRNeBfuhN0XKupJQ@mail.gmail.com>

On Wed, 30 Aug 2017 17:41:20 +0800
Bob Chen <a175818323@gmail.com> wrote:

> I think I have observed what you said...
> 
> The link speed on host remained 8GT/s until I finished running
> p2pBandwidthLatencyTest
> for the first time. Then it became 2.5GT/s...
> 
> 
> # lspci -s 09:00.0 -vvv
...
> LnkSta: Speed 8GT/s, Width x16, TrErr- Train- SlotClk+ DLActive- BWMgmt-

So long as the device renegotiates to 8GT/s under load rather than
getting stuck at 2.5GT/s, I think this is the expected behavior.  This
is a power saving measure by the driver.  Thanks,

Alex

  reply	other threads:[~2017-08-30 16:43 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4E0AFA5F-44D6-4624-A99F-68A7FE52F397@meituan.com>
     [not found] ` <4b31a711-a52e-25d3-4a7c-1be8521097d9@redhat.com>
     [not found]   ` <F99BFE80-FC15-40A0-BB3E-1B53B6CF9B05@meituan.com>
2017-07-26  6:21     ` [Qemu-devel] About virtio device hotplug in Q35! 【外域邮件.谨慎查阅】 Marcel Apfelbaum
2017-07-26 15:29       ` Alex Williamson
2017-07-26 16:06         ` Michael S. Tsirkin
2017-07-26 17:32           ` Alex Williamson
2017-08-01  5:04             ` Bob Chen
2017-08-01  5:46               ` Alex Williamson
2017-08-01  9:35                 ` Bob Chen
2017-08-01 14:39                   ` Michael S. Tsirkin
2017-08-01 15:01                   ` Alex Williamson
2017-08-07 13:00                     ` Bob Chen
2017-08-07 15:52                       ` Alex Williamson
2017-08-08  1:44                         ` Bob Chen
2017-08-08  8:06                           ` Bob Chen
2017-08-08 16:53                           ` Alex Williamson
2017-08-08 20:07                         ` Michael S. Tsirkin
2017-08-22  7:04                           ` Bob Chen
2017-08-22 16:56                             ` Alex Williamson
2017-08-22 18:06                               ` Michael S. Tsirkin
2017-08-29 10:41                                 ` Bob Chen
2017-08-29 14:13                                   ` Alex Williamson
2017-08-30  9:41                                     ` Bob Chen
2017-08-30 16:43                                       ` Alex Williamson [this message]
2017-09-01  9:58                                         ` Bob Chen
2017-11-30  8:06                                           ` Bob Chen
2017-08-07 13:04                     ` Bob Chen
2017-08-07 16:00                       ` Alex Williamson

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