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From: Logan Gunthorpe <logang@deltatee.com>
To: Dave Jiang <dave.jiang@intel.com>,
	linux-kernel@vger.kernel.org, linux-ntb@googlegroups.com,
	linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org,
	linux-kselftest@vger.kernel.org, Jon Mason <jdmason@kudzu.us>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Joerg Roedel <joro@8bytes.org>
Cc: Allen Hubbe <allenbh@gmail.com>,
	Serge Semin <fancer.lancer@gmail.com>,
	Eric Pilmore <epilmore@gigaio.com>
Subject: Re: [PATCH 0/9] Support using MSI interrupts in ntb_transport
Date: Thu, 31 Jan 2019 16:52:10 -0700	[thread overview]
Message-ID: <59a4f188-0d37-bf40-baf6-80b4fa46df52@deltatee.com> (raw)
In-Reply-To: <d46ce09c-d493-3d63-a854-b68a09345a75@intel.com>



On 2019-01-31 4:48 p.m., Dave Jiang wrote:
> 
> On 1/31/2019 4:41 PM, Logan Gunthorpe wrote:
>>
>> On 2019-01-31 3:46 p.m., Dave Jiang wrote:
>>> I believe irqbalance writes to the file /proc/irq/N/smp_affinity. So
>>> maybe take a look at the code that starts from there and see if it would
>>> have any impact on your stuff.
>> Ok, well on my system I can write to the smp_affinity all day and the
>> MSI interrupts still work fine.
> 
> Maybe your code is ok then. If the stats show up in /proc/interrupts 
> then you can see it moving to different cores.

Yes, I did check that the stats change CPU in proc interrupts.

> Yeah I'm not sure what to do about it either as I'm not super familiar 
> with that area either. Just making note of what I encountered. And you 
> are right, the updated info has to go over NTB for the other side to 
> write to the updated place. So there's a lot of latency involved.

Ok, well I'll implement the callback anyway for v2. Better safe than
sorry. We can operate on the assumption that someone thought of the race
condition and if we ever see reports of lost interrupts we'll know where
to look.

Logan

      reply	other threads:[~2019-01-31 23:52 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-31 18:56 [PATCH 0/9] Support using MSI interrupts in ntb_transport Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 1/9] iommu/vt-d: Allow interrupts from the entire bus for aliased devices Logan Gunthorpe
2019-02-01 16:44   ` Joerg Roedel
2019-02-01 17:27     ` Logan Gunthorpe
2019-02-05 19:19       ` Jacob Pan
2019-02-05 20:40         ` Logan Gunthorpe
2019-02-05 23:58           ` Jacob Pan
2019-01-31 18:56 ` [PATCH 2/9] PCI/MSI: Support allocating virtual MSI interrupts Logan Gunthorpe
2019-01-31 22:39   ` Bjorn Helgaas
2019-01-31 22:52     ` Logan Gunthorpe
2019-02-01 19:23       ` Bjorn Helgaas
2019-01-31 18:56 ` [PATCH 3/9] PCI/switchtec: Add module parameter to request more interrupts Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 4/9] NTB: Introduce functions to calculate multi-port resource index Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 5/9] NTB: Rename ntb.c to support multiple source files in the module Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 6/9] NTB: Introduce MSI library Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 7/9] NTB: Introduce NTB MSI Test Client Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 8/9] NTB: Add ntb_msi_test support to ntb_test Logan Gunthorpe
2019-01-31 18:56 ` [PATCH 9/9] NTB: Add MSI interrupt support to ntb_transport Logan Gunthorpe
2019-01-31 20:20 ` [PATCH 0/9] Support using MSI interrupts in ntb_transport Dave Jiang
2019-01-31 20:48   ` Logan Gunthorpe
2019-01-31 20:58     ` Dave Jiang
2019-01-31 22:39       ` Logan Gunthorpe
2019-01-31 22:46         ` Dave Jiang
2019-01-31 23:41           ` Logan Gunthorpe
2019-01-31 23:48             ` Dave Jiang
2019-01-31 23:52               ` Logan Gunthorpe [this message]

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