From: John Garry <john.garry@huawei.com>
To: <joro@8bytes.org>, <will@kernel.org>, <robin.murphy@arm.com>
Cc: <mst@redhat.com>, <jasowang@redhat.com>,
<baolu.lu@linux.intel.com>, <iommu@lists.linux-foundation.org>,
<linux-kernel@vger.kernel.org>,
<virtualization@lists.linux-foundation.org>, <hch@lst.de>,
<chenxiang66@hisilicon.com>, <linuxarm@huawei.com>
Subject: Re: [PATCH v5 0/5] iommu: Allow IOVA rcache range be configured
Date: Mon, 28 Feb 2022 09:44:19 +0000 [thread overview]
Message-ID: <a8158643-4bf3-2482-3d8e-ff75a31d5a7b@huawei.com> (raw)
In-Reply-To: <1644859746-20279-1-git-send-email-john.garry@huawei.com>
On 14/02/2022 17:29, John Garry wrote:
Hi guys,
And a friendly reminder on this series also.
Cheers,
john
> For streaming DMA mappings involving an IOMMU and whose IOVA len regularly
> exceeds the IOVA rcache upper limit (meaning that they are not cached),
> performance can be reduced.
>
> This may be much more pronounced from commit 4e89dce72521 ("iommu/iova:
> Retry from last rb tree node if iova search fails"), as discussed at [0].
>
> IOVAs which cannot be cached are highly involved in the IOVA ageing issue,
> as discussed at [1].
>
> This series allows the IOVA rcache range be configured, so that we may
> cache all IOVAs per domain, thus improving performance.
>
> A new IOMMU group sysfs file is added - max_opt_dma_size - which is used
> indirectly to configure the IOVA rcache range:
> /sys/kernel/iommu_groups/X/max_opt_dma_size
>
> This file is updated same as how the IOMMU group default domain type is
> updated, i.e. must unbind the only device in the group first.
>
> The inspiration here comes from block layer request queue sysfs
> "optimal_io_size" file, in /sys/block/sdX/queue/optimal_io_size
>
> Some old figures* for storage scenario (when increasing IOVA rcache range
> to cover all DMA mapping sizes from the LLD):
> v5.13-rc1 baseline: 1200K IOPS
> With series: 1800K IOPS
>
> All above are for IOMMU strict mode. Non-strict mode gives ~1800K IOPS in
> all scenarios.
>
> Based on v5.17-rc4 + [2]
> * I lost my high data throughout test setup
>
> Differences to v4:
> https://lore.kernel.org/linux-iommu/1626259003-201303-1-git-send-email-john.garry@huawei.com/
> - Major rebase
> - Change the "Refactor iommu_group_store_type()" to not use a callback
> and an op type enum instead
> - I didn't pick up Will's Ack as it has changed so much
> - Use a domain feature flag to keep same default group type
> - Add wrapper for default IOVA rcache range
> - Combine last 2x patches
>
> [0] https://lore.kernel.org/linux-iommu/20210129092120.1482-1-thunder.leizhen@huawei.com/
> [1] https://lore.kernel.org/linux-iommu/1607538189-237944-1-git-send-email-john.garry@huawei.com/
> [2] https://lore.kernel.org/linux-iommu/20220203063345-mutt-send-email-mst@kernel.org/T/#m5b2b59576d35cad544314470f32e5f40ac5d1fe9
>
> John Garry (5):
> iommu: Refactor iommu_group_store_type()
> iova: Allow rcache range upper limit to be flexible
> iommu: Allow iommu_change_dev_def_domain() realloc same default domain
> type
> iommu: Allow max opt DMA len be set for a group via sysfs
> iova: Add iova_len argument to iova_domain_init_rcaches()
>
> .../ABI/testing/sysfs-kernel-iommu_groups | 16 ++
> drivers/iommu/dma-iommu.c | 15 +-
> drivers/iommu/iommu.c | 202 +++++++++++++-----
> drivers/iommu/iova.c | 37 ++--
> drivers/vdpa/vdpa_user/iova_domain.c | 4 +-
> include/linux/iommu.h | 7 +
> include/linux/iova.h | 6 +-
> 7 files changed, 212 insertions(+), 75 deletions(-)
>
prev parent reply other threads:[~2022-02-28 9:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 17:29 [PATCH v5 0/5] iommu: Allow IOVA rcache range be configured John Garry
2022-02-14 17:29 ` [PATCH v5 1/5] iommu: Refactor iommu_group_store_type() John Garry
2022-02-14 17:29 ` [PATCH v5 2/5] iova: Allow rcache range upper limit to be flexible John Garry
2022-02-14 17:29 ` [PATCH v5 3/5] iommu: Allow iommu_change_dev_def_domain() realloc same default domain type John Garry
2022-02-14 17:29 ` [PATCH v5 4/5] iommu: Allow max opt DMA len be set for a group via sysfs John Garry
2022-02-14 17:29 ` [PATCH v5 5/5] iova: Add iova_len argument to iova_domain_init_rcaches() John Garry
2022-02-28 9:44 ` John Garry [this message]
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