From: Dan Williams <djbw@fb.com>
To: Jon Mason <jon.mason@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] ioatdma: add DMA_PRIVATE capabilities flag
Date: Thu, 27 Jun 2013 01:10:58 +0000 [thread overview]
Message-ID: <84A937D219C2B44EB8EA44831ACA1E4917266843@PRN-MBX01-3.TheFacebook.com> (raw)
In-Reply-To: <20130626235521.GH3344@jonmason-lab>
On 6/26/13 4:55 PM, "Jon Mason" <jon.mason@intel.com> wrote:
>Unfortunately, the dma_find_channel model does not led itself to
>optimal usage of the available channels, as it seems to give out the
>same channel. Adding some randomizer (or other way to spread the
>channel selection over multiple channels) would be greatly
>beneficial.
Right now the allocation scheme is per-cpu. If you have multiple
submission contexts on different cpus it should use all available channels.
>Alternatively, adding an async_memcpy_mmio function (and perhaps some
>minimal size to use the DMA engine) would provide a solution that
>would work.
It¹s hard. The size is arch and use specific so it may be best to leave
it up to the client.
>However, dma_find_channel should be sufficient to get NTB use of DMA
>engines out for review. I'll clean it up and send it out shortly.
>Thanks for the insight.
Cool, I¹ll take a look.
prev parent reply other threads:[~2013-06-27 1:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 0:46 [PATCH 0/2] DMA Offload fixes Jon Mason
2013-06-19 0:46 ` [PATCH 1/2] dmadevices: dma_sync_wait undefined Jon Mason
2013-06-19 1:13 ` Dan Williams
2013-06-19 16:28 ` Jon Mason
2013-06-20 21:20 ` Dan Williams
2013-06-26 23:47 ` Jon Mason
2013-06-19 0:46 ` [PATCH 2/2] ioatdma: add DMA_PRIVATE capabilities flag Jon Mason
2013-06-19 0:59 ` Dan Williams
2013-06-19 17:36 ` Dave Jiang
2013-06-19 17:52 ` Jon Mason
2013-06-19 18:56 ` Dan Williams
2013-06-19 20:10 ` Jon Mason
2013-06-19 20:44 ` Dan Williams
2013-06-26 23:55 ` Jon Mason
2013-06-27 1:10 ` Dan Williams [this message]
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