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From: Christoph Hellwig <hch@lst.de>
To: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>,
	tglx@linutronix.de, axboe@fb.com, linux-block@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: automatic interrupt affinity for MSI/MSI-X capable devices V2
Date: Thu, 16 Jun 2016 17:22:37 +0200	[thread overview]
Message-ID: <20160616152237.GB13615@lst.de> (raw)
In-Reply-To: <b8cdfc80-fa77-b7cc-69b8-fb6037114087@sandisk.com>

On Thu, Jun 16, 2016 at 11:45:55AM +0200, Bart Van Assche wrote:
> Is my interpretation correct that for an adapter that supports two 
> interrupts and on a system with eight CPU cores and no hyperthreading this 
> patch series will assign interrupt vector 0 to CPU 0 and interrupt vector 1 
> to CPU 1?

Yes - same as the existing blk-mq queue distribution.

> Are you aware that drivers like ib_srp assume that interrupts 
> have been spread evenly, that means assigning vector 0 to CPU 0 and vector 
> 1 to CPU 4?

which will make them run into a conflict with the current blk-mq
assignment.  That's exactly the point why we're trying to move things
to a core location so that everyone can use the same mapping.

WARNING: multiple messages have this Message-ID (diff)
From: hch@lst.de (Christoph Hellwig)
Subject: automatic interrupt affinity for MSI/MSI-X capable devices V2
Date: Thu, 16 Jun 2016 17:22:37 +0200	[thread overview]
Message-ID: <20160616152237.GB13615@lst.de> (raw)
In-Reply-To: <b8cdfc80-fa77-b7cc-69b8-fb6037114087@sandisk.com>

On Thu, Jun 16, 2016@11:45:55AM +0200, Bart Van Assche wrote:
> Is my interpretation correct that for an adapter that supports two 
> interrupts and on a system with eight CPU cores and no hyperthreading this 
> patch series will assign interrupt vector 0 to CPU 0 and interrupt vector 1 
> to CPU 1?

Yes - same as the existing blk-mq queue distribution.

> Are you aware that drivers like ib_srp assume that interrupts 
> have been spread evenly, that means assigning vector 0 to CPU 0 and vector 
> 1 to CPU 4?

which will make them run into a conflict with the current blk-mq
assignment.  That's exactly the point why we're trying to move things
to a core location so that everyone can use the same mapping.

  reply	other threads:[~2016-06-16 15:22 UTC|newest]

Thread overview: 129+ 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
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 [this message]
2016-06-16 15:22     ` Christoph Hellwig
2016-06-26 19:40 ` Alexander Gordeev
2016-06-26 19:40   ` Alexander Gordeev

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