From: Sinan Kaya <okaya@codeaurora.org>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Myron Stowe <myron.stowe@gmail.com>,
Ron Yuan <ron.yuan@memblaze.com>,
Radjendirane Codandaramane <radjendirane.codanda@microsemi.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Bo Chen <bo.chen@memblaze.com>,
William Huang <william.huang@memblaze.com>,
Fengming Wu <fengming.wu@memblaze.com>,
Jason Jiang <jason.jiang@microsemi.com>,
Ramyakanth Edupuganti <Ramyakanth.Edupuganti@microsemi.com>,
William Cheng <william.cheng@microsemi.com>,
"Kim Helper (khelper)" <khelper@micron.com>,
Linux PCI <linux-pci@vger.kernel.org>
Subject: Re: One Question About PCIe BUS Config Type with pcie_bus_safe or pcie_bus_perf On NVMe Device
Date: Sun, 4 Feb 2018 20:02:03 -0500 [thread overview]
Message-ID: <7ae35971-1e85-c3ca-9fbf-6c2ab5883313@codeaurora.org> (raw)
In-Reply-To: <31eecdff-68e7-4891-5034-9a387e79a97b@codeaurora.org>
On 2/1/2018 10:14 AM, Sinan Kaya wrote:
> I think from above examples:
> 1. perf mode is moving devices to 256 MPS as it can.
> 2. safe mode is setting to 128 MPS
> 3. perf mode set MRRS=MPS is a CORRECT call for device with MPSC lower than its parents.
Thinking more about this...
The only way for a transaction of size that's greater than MRRS can happen if there
is a device specific driver attached that sends commands to the device and device issues
a large sized memory read transaction.
Let's say that we find the slow device in tree.
If no driver is attached to a slow device in the tree and assume it is safe and do not
reduce MRRS?
> 4. perf mode set MRRS=MPS is not necessary for a device with SAME MPSC as its parents?
> 5. it is an interested point to me that slot/switch/root MRRS are always set to 128B, I have not found out why.
--
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
prev parent reply other threads:[~2018-02-05 1:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <SH2PR01MB106A1E21DEB5FE3FFB3D61C83E90@SH2PR01MB106.CHNPR01.prod.partner.outlook.cn>
[not found] ` <ef16a3cc-b641-a30d-644a-7940e340eb3e@codeaurora.org>
[not found] ` <SHAPR01MB173A5EA1677C2138CB528F2FEE90@SHAPR01MB173.CHNPR01.prod.partner.outlook.cn>
[not found] ` <5727b0b1-f0d5-7c78-373e-fc9d1bd662d2@codeaurora.org>
[not found] ` <CABhMZUU0643U-qVc9ymA+1PMZToSLFm2dg8-cu=iQ2LGw2Pi8Q@mail.gmail.com>
[not found] ` <SHAPR01MB173A36104635A8BFF9A83E1FEE80@SHAPR01MB173.CHNPR01.prod.partner.outlook.cn>
2018-01-18 16:24 ` One Question About PCIe BUS Config Type with pcie_bus_safe or pcie_bus_perf On NVMe Device Sinan Kaya
2018-01-19 20:51 ` Bjorn Helgaas
2018-01-20 19:20 ` Sinan Kaya
2018-01-20 19:29 ` Sinan Kaya
2018-01-22 21:36 ` Bjorn Helgaas
2018-01-22 22:04 ` Sinan Kaya
2018-01-22 22:51 ` Bjorn Helgaas
2018-01-22 23:24 ` Sinan Kaya
2018-01-23 0:16 ` Bjorn Helgaas
2018-01-23 2:27 ` Sinan Kaya
2018-01-23 13:25 ` Ron Yuan
2018-01-23 14:01 ` Ron Yuan
2018-01-23 17:48 ` Bjorn Helgaas
2018-01-23 18:07 ` Bjorn Helgaas
2018-01-23 14:38 ` Bjorn Helgaas
2018-01-23 23:50 ` Radjendirane Codandaramane
2018-01-24 16:29 ` Myron Stowe
2018-01-24 17:59 ` Ron Yuan
2018-01-24 18:01 ` Bjorn Helgaas
2018-01-31 8:40 ` Ron Yuan
2018-02-01 0:01 ` Myron Stowe
2018-02-01 0:13 ` Sinan Kaya
2018-02-01 3:37 ` Bjorn Helgaas
2018-02-01 15:14 ` Sinan Kaya
2018-02-05 1:02 ` Sinan Kaya [this message]
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