From: Ming Lei <ming.lei@redhat.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: iommu@lists.linux-foundation.org, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [bug report] iommu_dma_unmap_sg() is very slow then running IO from remote numa node
Date: Fri, 9 Jul 2021 22:24:58 +0800 [thread overview]
Message-ID: <YOhcOv1oOwm6fco+@T590> (raw)
In-Reply-To: <23e7956b-f3b5-b585-3c18-724165994051@arm.com>
On Fri, Jul 09, 2021 at 11:26:53AM +0100, Robin Murphy wrote:
> On 2021-07-09 09:38, Ming Lei wrote:
> > Hello,
> >
> > I observed that NVMe performance is very bad when running fio on one
> > CPU(aarch64) in remote numa node compared with the nvme pci numa node.
> >
> > Please see the test result[1] 327K vs. 34.9K.
> >
> > Latency trace shows that one big difference is in iommu_dma_unmap_sg(),
> > 1111 nsecs vs 25437 nsecs.
>
> Are you able to dig down further into that? iommu_dma_unmap_sg() itself
> doesn't do anything particularly special, so whatever makes a difference is
> probably happening at a lower level, and I suspect there's probably an SMMU
> involved. If for instance it turns out to go all the way down to
> __arm_smmu_cmdq_poll_until_consumed() because polling MMIO from the wrong
> node is slow, there's unlikely to be much you can do about that other than
> the global "go faster" knobs (iommu.strict and iommu.passthrough) with their
> associated compromises.
Follows the log of 'perf report'
1) good(run fio from cpus in the nvme's numa node)
- 34.86% 1.73% fio [nvme] [k] nvme_process_cq ▒
- 33.13% nvme_process_cq ▒
- 32.93% nvme_pci_complete_rq ▒
- 24.92% nvme_unmap_data ▒
- 20.08% dma_unmap_sg_attrs ▒
- 19.79% iommu_dma_unmap_sg ▒
- 19.55% __iommu_dma_unmap ▒
- 16.86% arm_smmu_iotlb_sync ▒
- 16.81% arm_smmu_tlb_inv_range_domain ▒
- 14.73% __arm_smmu_tlb_inv_range ▒
14.44% arm_smmu_cmdq_issue_cmdlist ▒
0.89% __pi_memset ▒
0.75% arm_smmu_atc_inv_domain ▒
+ 1.58% iommu_unmap_fast ▒
+ 0.71% iommu_dma_free_iova ▒
- 3.25% dma_unmap_page_attrs ▒
- 3.21% iommu_dma_unmap_page ▒
- 3.14% __iommu_dma_unmap_swiotlb ▒
- 2.86% __iommu_dma_unmap ▒
- 2.48% arm_smmu_iotlb_sync ▒
- 2.47% arm_smmu_tlb_inv_range_domain ▒
- 2.19% __arm_smmu_tlb_inv_range ▒
2.16% arm_smmu_cmdq_issue_cmdlist ▒
+ 1.34% mempool_free ▒
+ 7.68% nvme_complete_rq ▒
+ 1.73% _start
2) bad(run fio from cpus not in the nvme's numa node)
- 49.25% 3.03% fio [nvme] [k] nvme_process_cq ▒
- 46.22% nvme_process_cq ▒
- 46.07% nvme_pci_complete_rq ▒
- 41.02% nvme_unmap_data ▒
- 34.92% dma_unmap_sg_attrs ▒
- 34.75% iommu_dma_unmap_sg ▒
- 34.58% __iommu_dma_unmap ▒
- 33.04% arm_smmu_iotlb_sync ▒
- 33.00% arm_smmu_tlb_inv_range_domain ▒
- 31.86% __arm_smmu_tlb_inv_range ▒
31.71% arm_smmu_cmdq_issue_cmdlist ▒
+ 0.90% iommu_unmap_fast ▒
- 5.17% dma_unmap_page_attrs ▒
- 5.15% iommu_dma_unmap_page ▒
- 5.12% __iommu_dma_unmap_swiotlb ▒
- 5.05% __iommu_dma_unmap ▒
- 4.86% arm_smmu_iotlb_sync ▒
- 4.85% arm_smmu_tlb_inv_range_domain ▒
- 4.70% __arm_smmu_tlb_inv_range ▒
4.67% arm_smmu_cmdq_issue_cmdlist ▒
+ 0.74% mempool_free ▒
+ 4.83% nvme_complete_rq ▒
+ 3.03% _start
Thanks,
Ming
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-07-09 14:25 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 8:38 [bug report] iommu_dma_unmap_sg() is very slow then running IO from remote numa node Ming Lei
2021-07-09 10:16 ` Russell King (Oracle)
2021-07-09 14:21 ` Ming Lei
2021-07-09 10:26 ` Robin Murphy
2021-07-09 11:04 ` John Garry
2021-07-09 12:34 ` Robin Murphy
2021-07-09 14:24 ` Ming Lei [this message]
2021-07-19 16:14 ` John Garry
2021-07-21 1:40 ` Ming Lei
2021-07-21 9:23 ` John Garry
2021-07-21 9:59 ` Ming Lei
2021-07-21 11:07 ` John Garry
2021-07-21 11:58 ` Ming Lei
2021-07-22 7:58 ` Ming Lei
2021-07-22 10:05 ` John Garry
2021-07-22 10:19 ` Ming Lei
2021-07-22 11:12 ` John Garry
2021-07-22 12:53 ` Marc Zyngier
2021-07-22 13:54 ` John Garry
2021-07-22 15:54 ` Ming Lei
2021-07-22 17:40 ` Robin Murphy
2021-07-23 10:21 ` Ming Lei
2021-07-26 7:51 ` John Garry
2021-07-28 1:32 ` Ming Lei
2021-07-28 10:38 ` John Garry
2021-07-28 15:17 ` Ming Lei
2021-07-28 15:39 ` Robin Murphy
2021-08-10 9:36 ` John Garry
2021-08-10 10:35 ` Ming Lei
2021-07-27 17:08 ` Robin Murphy
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=YOhcOv1oOwm6fco+@T590 \
--to=ming.lei@redhat.com \
--cc=iommu@lists.linux-foundation.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=robin.murphy@arm.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).