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From: John Garry <john.garry@huawei.com>
To: <will@kernel.org>, <robin.murphy@arm.com>
Cc: <joro@8bytes.org>, <trivial@kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<iommu@lists.linux-foundation.org>,
	<linux-kernel@vger.kernel.org>, <linuxarm@huawei.com>,
	<maz@kernel.org>, "John Garry" <john.garry@huawei.com>
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


WARNING: multiple messages have this Message-ID (diff)
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

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

             reply	other threads:[~2020-06-22 17:32 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-22 17:28 John Garry [this message]
2020-06-22 17:28 ` [PATCH 0/4] iommu/arm-smmu-v3: Improve cmdq lock efficiency John Garry
2020-06-22 17:28 ` [PATCH 1/4] iommu/arm-smmu-v3: Fix trivial typo John Garry
2020-06-22 17:28   ` 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   ` 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   ` John Garry
2020-06-22 17:28 ` [PATCH 4/4] iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist() John Garry
2020-06-22 17:28   ` John Garry
2020-06-23  1:07   ` kernel test robot
2020-06-23  1:07     ` kernel test robot
2020-06-23  1:07     ` kernel test robot
2020-06-23  9:21     ` John Garry
2020-06-23  9:21       ` John Garry
2020-06-23  9:21       ` John Garry
2020-06-23  9:35       ` Rikard Falkeborn
2020-06-23 10:19         ` John Garry
2020-06-23 10:19           ` John Garry
2020-06-23 10:19           ` John Garry
2020-06-23 13:55           ` Rikard Falkeborn
2020-06-26 10:05             ` John Garry
2020-06-26 10:05               ` John Garry
2020-06-26 10:05               ` John Garry
2020-06-26 10:05               ` John Garry
2020-06-23 16:22       ` Robin Murphy
2020-06-23 16:22         ` Robin Murphy
2020-06-23 16:22         ` Robin Murphy
2020-06-23 16:22         ` Robin Murphy
2020-06-24  8:15         ` John Garry
2020-06-24  8:15           ` John Garry
2020-06-24  8:15           ` John Garry
2020-06-24  8:15           ` John Garry
2020-07-16 10:20   ` Will Deacon
2020-07-16 10:20     ` Will Deacon
2020-07-16 10:20     ` Will Deacon
2020-07-16 10:26     ` John Garry
2020-07-16 10:26       ` John Garry
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
2020-07-08 13:00   ` John Garry
2020-07-08 13:00   ` John Garry
2020-07-16 10:19 ` Will Deacon
2020-07-16 10:19   ` Will Deacon
2020-07-16 10:19   ` Will Deacon
2020-07-16 10:22   ` Will Deacon
2020-07-16 10:22     ` Will Deacon
2020-07-16 10:22     ` Will Deacon
2020-07-16 10:28     ` Will Deacon
2020-07-16 10:28       ` Will Deacon
2020-07-16 10:28       ` Will Deacon
2020-07-16 10:56       ` John Garry
2020-07-16 10:56         ` John Garry
2020-07-16 10:56         ` John Garry
2020-07-16 11:22         ` Robin Murphy
2020-07-16 11:22           ` Robin Murphy
2020-07-16 11:22           ` Robin Murphy
2020-07-16 11:30           ` John Garry
2020-07-16 11:30             ` John Garry
2020-07-16 11:30             ` John Garry
2020-07-16 11:32           ` Will Deacon
2020-07-16 11:32             ` Will Deacon
2020-07-16 11:32             ` Will Deacon
2020-07-16 16:50             ` John Garry
2020-07-16 16:50               ` John Garry
2020-07-16 16:50               ` John Garry
2020-07-16 13:31       ` John Garry
2020-07-16 13:31         ` John Garry
2020-07-16 13:31         ` John Garry

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