From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: "Isaac J. Manjarres" <isaacm@codeaurora.org>,
pdaly@codeaurora.org, will@kernel.org,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
pratikp@codeaurora.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 0/5] Optimize iommu_map_sg() performance
Date: Tue, 12 Jan 2021 16:33:07 +0000 [thread overview]
Message-ID: <20210112163307.GA1199965@infradead.org> (raw)
In-Reply-To: <8ad6db90-1d86-db2a-ccb5-dc3f01213289@arm.com>
On Tue, Jan 12, 2021 at 04:00:59PM +0000, Robin Murphy wrote:
> Out of curiosity, how much of the difference is attributable to actual
> indirect call overhead vs. the additional massive reduction in visits to
> arm_smmu_rpm_{get,put} that you fail to mention? There are ways to optimise
> indirect calling that would benefit *all* cases, rather than just one
> operation for one particular driver.
Do we have systems that use different iommu_ops at the same time?
If not this would be a prime candidate for static call optimizations.
Also I've been pondering adding direct calls to the iommu dma ops like
we do for DMA direct. This would allow to stop using dma_ops entirely
for arm64.
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next prev parent reply other threads:[~2021-01-12 16:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 14:54 [PATCH v2 0/5] Optimize iommu_map_sg() performance Isaac J. Manjarres
2021-01-11 14:54 ` [PATCH v2 1/5] iommu/io-pgtable: Introduce map_sg() as a page table op Isaac J. Manjarres
2021-01-11 14:54 ` [PATCH v2 2/5] iommu/io-pgtable-arm: Hook up map_sg() Isaac J. Manjarres
2021-01-11 14:54 ` [PATCH v2 3/5] iommu/io-pgtable-arm-v7s: " Isaac J. Manjarres
2021-01-11 14:54 ` [PATCH v2 4/5] iommu: Introduce map_sg() as an IOMMU op for IOMMU drivers Isaac J. Manjarres
2021-01-11 14:54 ` [PATCH v2 5/5] iommu/arm-smmu: Hook up map_sg() Isaac J. Manjarres
2021-01-12 16:00 ` [PATCH v2 0/5] Optimize iommu_map_sg() performance Robin Murphy
2021-01-12 16:33 ` Christoph Hellwig [this message]
2021-01-13 2:54 ` Robin Murphy
2021-01-21 21:30 ` isaacm
2021-01-22 13:44 ` Robin Murphy
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