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From: Bart Van Assche <bart.vanassche@sandisk.com>
To: Christoph Hellwig <hch@lst.de>, <tglx@linutronix.de>, <axboe@fb.com>
Cc: <linux-block@vger.kernel.org>, <linux-pci@vger.kernel.org>,
	<linux-nvme@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 02/13] irq: Introduce IRQD_AFFINITY_MANAGED flag
Date: Wed, 15 Jun 2016 10:44:37 +0200	[thread overview]
Message-ID: <0412b942-ea0d-d4eb-c724-8243d12ff6f3@sandisk.com> (raw)
In-Reply-To: <1465934346-20648-3-git-send-email-hch@lst.de>

On 06/14/2016 09:58 PM, Christoph Hellwig wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
>
> Interupts marked with this flag are excluded from user space interrupt
> affinity changes. Contrary to the IRQ_NO_BALANCING flag, the kernel internal
> affinity mechanism is not blocked.
>
> This flag will be used for multi-queue device interrupts.

It's great to see that the goal of this patch series is to configure 
interrupt affinity automatically for adapters that support multiple 
MSI-X vectors. However, is excluding these interrupts from irqbalanced 
really the way to go? Suppose e.g. that a system is equipped with two 
RDMA adapters, that these adapters are used by a blk-mq enabled block 
initiator driver and that each adapter supports eight MSI-X vectors. 
Should the interrupts of the two RDMA adapters be assigned to different 
CPU cores? If so, which software layer should realize this? The kernel 
or user space?

Sorry that I missed the first version of this patch series.

Thanks,

Bart.

WARNING: multiple messages have this Message-ID (diff)
From: bart.vanassche@sandisk.com (Bart Van Assche)
Subject: [PATCH 02/13] irq: Introduce IRQD_AFFINITY_MANAGED flag
Date: Wed, 15 Jun 2016 10:44:37 +0200	[thread overview]
Message-ID: <0412b942-ea0d-d4eb-c724-8243d12ff6f3@sandisk.com> (raw)
In-Reply-To: <1465934346-20648-3-git-send-email-hch@lst.de>

On 06/14/2016 09:58 PM, Christoph Hellwig wrote:
> From: Thomas Gleixner <tglx at linutronix.de>
>
> Interupts marked with this flag are excluded from user space interrupt
> affinity changes. Contrary to the IRQ_NO_BALANCING flag, the kernel internal
> affinity mechanism is not blocked.
>
> This flag will be used for multi-queue device interrupts.

It's great to see that the goal of this patch series is to configure 
interrupt affinity automatically for adapters that support multiple 
MSI-X vectors. However, is excluding these interrupts from irqbalanced 
really the way to go? Suppose e.g. that a system is equipped with two 
RDMA adapters, that these adapters are used by a blk-mq enabled block 
initiator driver and that each adapter supports eight MSI-X vectors. 
Should the interrupts of the two RDMA adapters be assigned to different 
CPU cores? If so, which software layer should realize this? The kernel 
or user space?

Sorry that I missed the first version of this patch series.

Thanks,

Bart.

  reply	other threads:[~2016-06-15  8:44 UTC|newest]

Thread overview: 132+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-14 19:58 automatic interrupt affinity for MSI/MSI-X capable devices V2 Christoph Hellwig
2016-06-14 19:58 ` Christoph Hellwig
2016-06-14 19:58 ` [PATCH 01/13] irq/msi: Remove unused MSI_FLAG_IDENTITY_MAP Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-16  9:05   ` Bart Van Assche
2016-06-16  9:05     ` Bart Van Assche
2016-06-14 19:58 ` [PATCH 02/13] irq: Introduce IRQD_AFFINITY_MANAGED flag Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-15  8:44   ` Bart Van Assche [this message]
2016-06-15  8:44     ` Bart Van Assche
2016-06-15 10:23     ` Christoph Hellwig
2016-06-15 10:23       ` Christoph Hellwig
2016-06-15 10:42       ` Bart Van Assche
2016-06-15 10:42         ` Bart Van Assche
2016-06-15 10:42         ` Bart Van Assche
2016-06-15 15:14         ` Keith Busch
2016-06-15 15:14           ` Keith Busch
2016-06-15 15:28           ` Bart Van Assche
2016-06-15 15:28             ` Bart Van Assche
2016-06-15 16:03             ` Keith Busch
2016-06-15 16:03               ` Keith Busch
2016-06-15 19:36               ` Bart Van Assche
2016-06-15 19:36                 ` Bart Van Assche
2016-06-15 20:06                 ` Keith Busch
2016-06-15 20:06                   ` Keith Busch
2016-06-15 20:12                   ` Keith Busch
2016-06-15 20:12                     ` Keith Busch
2016-06-15 20:50                     ` Bart Van Assche
2016-06-15 20:50                       ` Bart Van Assche
2016-06-16 15:19                       ` Keith Busch
2016-06-16 15:19                         ` Keith Busch
2016-06-22 11:56                         ` Alexander Gordeev
2016-06-22 11:56                           ` Alexander Gordeev
2016-06-22 11:56                           ` Alexander Gordeev
2016-06-16 15:20                 ` Christoph Hellwig
2016-06-16 15:20                   ` Christoph Hellwig
2016-06-16 15:39                   ` Bart Van Assche
2016-06-16 15:39                     ` Bart Van Assche
2016-06-20 12:22                     ` Christoph Hellwig
2016-06-20 12:22                       ` Christoph Hellwig
2016-06-20 12:22                       ` Christoph Hellwig
2016-06-20 13:21                       ` Bart Van Assche
2016-06-20 13:21                         ` Bart Van Assche
2016-06-20 13:21                         ` Bart Van Assche
2016-06-21 14:31                         ` Christoph Hellwig
2016-06-21 14:31                           ` Christoph Hellwig
2016-06-21 14:31                           ` Christoph Hellwig
2016-06-16  9:08   ` Bart Van Assche
2016-06-16  9:08     ` Bart Van Assche
2016-06-14 19:58 ` [PATCH 03/13] irq: Add affinity hint to irq allocation Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58 ` [PATCH 04/13] irq: Use affinity hint in irqdesc allocation Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58 ` [PATCH 05/13] irq/msi: Make use of affinity aware allocations Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58 ` [PATCH 06/13] irq: add a helper spread an affinity mask for MSI/MSI-X vectors Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 19:58   ` Christoph Hellwig
2016-06-14 21:54   ` Guilherme G. Piccoli
2016-06-14 21:54     ` Guilherme G. Piccoli
2016-06-15  8:35     ` Bart Van Assche
2016-06-15  8:35       ` Bart Van Assche
2016-06-15  8:35       ` Bart Van Assche
2016-06-15 10:10     ` Christoph Hellwig
2016-06-15 10:10       ` Christoph Hellwig
2016-06-15 13:09       ` Guilherme G. Piccoli
2016-06-15 13:09         ` Guilherme G. Piccoli
2016-06-16 15:16         ` Christoph Hellwig
2016-06-16 15:16           ` Christoph Hellwig
2016-06-25 20:05   ` Alexander Gordeev
2016-06-25 20:05     ` Alexander Gordeev
2016-06-30 17:48     ` Christoph Hellwig
2016-06-30 17:48       ` Christoph Hellwig
2016-06-30 17:48       ` Christoph Hellwig
2016-07-01  7:25       ` Alexander Gordeev
2016-07-01  7:25         ` Alexander Gordeev
2016-06-14 19:59 ` [PATCH 07/13] pci: Provide sensible irq vector alloc/free routines Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-23 11:16   ` Alexander Gordeev
2016-06-23 11:16     ` Alexander Gordeev
2016-06-30 16:54     ` Christoph Hellwig
2016-06-30 16:54       ` Christoph Hellwig
2016-06-30 17:28       ` Alexander Gordeev
2016-06-30 17:28         ` Alexander Gordeev
2016-06-30 17:35         ` Christoph Hellwig
2016-06-30 17:35           ` Christoph Hellwig
2016-06-14 19:59 ` [PATCH 08/13] pci: spread interrupt vectors in pci_alloc_irq_vectors Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-25 20:22   ` Alexander Gordeev
2016-06-25 20:22     ` Alexander Gordeev
2016-06-14 19:59 ` [PATCH 09/13] blk-mq: don't redistribute hardware queues on a CPU hotplug event Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59 ` [PATCH 10/13] blk-mq: only allocate a single mq_map per tag_set Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59 ` [PATCH 11/13] blk-mq: allow the driver to pass in an affinity mask Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-07-04  8:15   ` Alexander Gordeev
2016-07-04  8:15     ` Alexander Gordeev
2016-07-04  8:38     ` Christoph Hellwig
2016-07-04  8:38       ` Christoph Hellwig
2016-07-04  9:35       ` Alexander Gordeev
2016-07-04  9:35         ` Alexander Gordeev
2016-07-10  3:41         ` Christoph Hellwig
2016-07-10  3:41           ` Christoph Hellwig
2016-07-12  6:42           ` Alexander Gordeev
2016-07-12  6:42             ` Alexander Gordeev
2016-06-14 19:59 ` [PATCH 12/13] nvme: switch to use pci_alloc_irq_vectors Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59 ` [PATCH 13/13] nvme: remove the post_scan callout Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-14 19:59   ` Christoph Hellwig
2016-06-16  9:45 ` automatic interrupt affinity for MSI/MSI-X capable devices V2 Bart Van Assche
2016-06-16  9:45   ` Bart Van Assche
2016-06-16  9:45   ` Bart Van Assche
2016-06-16 15:22   ` Christoph Hellwig
2016-06-16 15:22     ` Christoph Hellwig
2016-06-26 19:40 ` Alexander Gordeev
2016-06-26 19:40   ` Alexander Gordeev
2016-07-04  8:39 automatic interrupt affinity for MSI/MSI-X capable devices V3 Christoph Hellwig
2016-07-04  8:39 ` [PATCH 02/13] irq: Introduce IRQD_AFFINITY_MANAGED flag Christoph Hellwig
2016-07-04  8:39   ` Christoph Hellwig
2016-07-04  8:39   ` Christoph Hellwig

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