From: John Garry <john.garry@huawei.com>
To: <will@kernel.org>, <robin.murphy@arm.com>
Cc: trivial@kernel.org, maz@kernel.org, linuxarm@huawei.com,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 0/4] iommu/arm-smmu-v3: Improve cmdq lock efficiency
Date: Tue, 23 Jun 2020 01:28:36 +0800 [thread overview]
Message-ID: <1592846920-45338-1-git-send-email-john.garry@huawei.com> (raw)
As mentioned in [0], the CPU may consume many cycles processing
arm_smmu_cmdq_issue_cmdlist(). One issue we find is the cmpxchg() loop to
get space on the queue takes approx 25% of the cycles for this function.
This series removes that cmpxchg().
For my NVMe test with 3x NVMe SSDs, I'm getting a ~24% throughput
increase:
Before: 1310 IOPs
After: 1630 IOPs
I also have a test harness to check the rate of DMA map+unmaps we can
achieve:
CPU count 32 64 128
Before: 63187 19418 10169
After: 93287 44789 15862
(unit is map+unmaps per CPU per second)
[0] https://lore.kernel.org/linux-iommu/B926444035E5E2439431908E3842AFD24B86DB@DGGEMI525-MBS.china.huawei.com/T/#ma02e301c38c3e94b7725e685757c27e39c7cbde3
John Garry (4):
iommu/arm-smmu-v3: Fix trivial typo
iommu/arm-smmu-v3: Calculate bits for prod and owner
iommu/arm-smmu-v3: Always issue a CMD_SYNC per batch
iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist()
drivers/iommu/arm-smmu-v3.c | 233 +++++++++++++++++++++++-------------
1 file changed, 151 insertions(+), 82 deletions(-)
--
2.26.2
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next reply other threads:[~2020-06-22 17:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-22 17:28 John Garry [this message]
2020-06-22 17:28 ` [PATCH 1/4] iommu/arm-smmu-v3: Fix trivial typo John Garry
2020-06-22 17:28 ` [PATCH 2/4] iommu/arm-smmu-v3: Calculate bits for prod and owner John Garry
2020-06-22 17:28 ` [PATCH 3/4] iommu/arm-smmu-v3: Always issue a CMD_SYNC per batch John Garry
2020-06-22 17:28 ` [PATCH 4/4] iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist() John Garry
2020-06-23 1:07 ` kernel test robot
2020-06-23 9:21 ` John Garry
2020-06-23 9:35 ` Rikard Falkeborn
2020-06-23 10:19 ` John Garry
2020-06-23 13:55 ` Rikard Falkeborn
2020-06-26 10:05 ` John Garry
2020-06-23 16:22 ` Robin Murphy
2020-06-24 8:15 ` John Garry
2020-07-16 10:20 ` Will Deacon
2020-07-16 10:26 ` John Garry
2020-07-08 13:00 ` [PATCH 0/4] iommu/arm-smmu-v3: Improve cmdq lock efficiency John Garry
2020-07-16 10:19 ` Will Deacon
2020-07-16 10:22 ` Will Deacon
2020-07-16 10:28 ` Will Deacon
2020-07-16 10:56 ` John Garry
2020-07-16 11:22 ` Robin Murphy
2020-07-16 11:30 ` John Garry
2020-07-16 11:32 ` Will Deacon
2020-07-16 16:50 ` John Garry
2020-07-16 13:31 ` John Garry
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