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 18:54:01 +0100 [thread overview]
Message-ID: <9b1d155e-28cc-08dc-5a5a-8580132575e7@huawei.com> (raw)
In-Reply-To: <a2585983-75d7-c627-13ba-38a464cf716e@acm.org>
On 09/06/2022 18:18, Bart Van Assche wrote:
>>>
>>> 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)?
>
> Hmm ... what exactly do you want me to test? Do you perhaps want me to
> measure how much performance drops with an IOMMU enabled?
Yes, I would like to know of any performance change with an IOMMU
enabled and then with an IOMMU enabled and including my series.
> I don't have
> access anymore to the SRP setup I referred to in my previous email. But
> I do have access to devices that boot from UFS storage. For these
> devices we need to transfer 2 MiB per request to achieve full bandwidth.
ok, but do you have a system where the UFS host controller is behind an
IOMMU? I had the impression that UFS controllers would be mostly found
in embedded systems and IOMMUs are not as common on there.
Thanks,
John
next prev parent reply other threads:[~2022-06-09 17:54 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
2022-06-09 17:18 ` Bart Van Assche
2022-06-09 17:54 ` John Garry [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9b1d155e-28cc-08dc-5a5a-8580132575e7@huawei.com \
--to=john.garry@huawei.com \
--cc=bvanassche@acm.org \
--cc=chenxiang66@hisilicon.com \
--cc=damien.lemoal@opensource.wdc.com \
--cc=hch@lst.de \
--cc=iommu@lists.linux-foundation.org \
--cc=jejb@linux.ibm.com \
--cc=joro@8bytes.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-ide@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=liyihang6@hisilicon.com \
--cc=m.szyprowski@samsung.com \
--cc=martin.petersen@oracle.com \
--cc=robin.murphy@arm.com \
--cc=thunder.leizhen@huawei.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).