From: John Garry <john.garry@huawei.com>
To: Bart Van Assche <bvanassche@acm.org>,
<damien.lemoal@opensource.wdc.com>, <joro@8bytes.org>,
<will@kernel.org>, <jejb@linux.ibm.com>,
<martin.petersen@oracle.com>, <hch@lst.de>,
<m.szyprowski@samsung.com>, <robin.murphy@arm.com>
Cc: <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-ide@vger.kernel.org>, <iommu@lists.linux-foundation.org>,
<linux-scsi@vger.kernel.org>, <liyihang6@hisilicon.com>,
<chenxiang66@hisilicon.com>, <thunder.leizhen@huawei.com>
Subject: Re: [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits
Date: Thu, 9 Jun 2022 09:00:50 +0100 [thread overview]
Message-ID: <5b214e95-dd95-551a-496e-a2139a74e8eb@huawei.com> (raw)
In-Reply-To: <bccbcc9b-4750-a1a7-130f-69eeea5dcb23@acm.org>
On 08/06/2022 22:07, Bart Van Assche wrote:
> On 6/8/22 10:50, John Garry wrote:
>> Please note that this limit only applies if we have an IOMMU enabled
>> for the scsi host dma device. Otherwise we are limited by dma direct
>> or swiotlb max mapping size, as before.
>
> SCSI host bus adapters that support 64-bit DMA may support much larger
> transfer sizes than 128 KiB.
Indeed, and that is my problem today, as my storage controller is
generating DMA mapping lengths which exceeds 128K and they slow
everything down.
If you say that SRP enjoys best peformance with larger transfers then
can you please test this with an IOMMU enabled (iommu group type DMA or
DMA-FQ)?
Thanks,
John
next prev parent reply other threads:[~2022-06-09 8:01 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-06 9:30 [PATCH v3 0/4] DMA mapping changes for SCSI core John Garry
2022-06-06 9:30 ` [PATCH v3 1/4] dma-mapping: Add dma_opt_mapping_size() John Garry
2022-06-08 17:27 ` Bart Van Assche
2022-06-06 9:30 ` [PATCH v3 2/4] dma-iommu: Add iommu_dma_opt_mapping_size() John Garry
2022-06-08 17:26 ` Bart Van Assche
2022-06-08 17:39 ` John Garry
2022-06-14 13:12 ` John Garry
2022-06-23 8:38 ` John Garry
2022-06-06 9:30 ` [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits John Garry
2022-06-08 17:33 ` Bart Van Assche
2022-06-08 17:50 ` John Garry
2022-06-08 21:07 ` Bart Van Assche
2022-06-09 8:00 ` John Garry [this message]
2022-06-09 17:18 ` Bart Van Assche
2022-06-09 17:54 ` John Garry
2022-06-09 20:34 ` Bart Van Assche
2022-06-10 15:37 ` John Garry
2022-06-23 8:36 ` John Garry
2022-06-06 9:30 ` [PATCH v3 4/4] libata-scsi: Cap ata_device->max_sectors according to shost->max_sectors John Garry
2022-06-07 22:43 ` [PATCH v3 0/4] DMA mapping changes for SCSI core Bart Van Assche
2022-06-08 10:14 ` John Garry
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