diff mbox series

[v4,05/20] iommu/tegra: gart: Optimize mapping / unmapping performance

Message ID 20180924004153.8232-6-digetx@gmail.com
State Deferred
Headers show
Series IOMMU: Tegra GART driver clean up and optimization | expand

Commit Message

Dmitry Osipenko Sept. 24, 2018, 12:41 a.m. UTC 
Currently GART writes one page entry at a time. More optimal would be to
aggregate the writes and flush BUS buffer in the end, this gives map/unmap
10-40% performance boost (depending on size of mapping) in comparison to
flushing after each page entry update.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/iommu/tegra-gart.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Comments

Thierry Reding Sept. 24, 2018, 10:07 a.m. UTC | #1 
On Mon, Sep 24, 2018 at 03:41:38AM +0300, Dmitry Osipenko wrote:
> Currently GART writes one page entry at a time. More optimal would be to
> aggregate the writes and flush BUS buffer in the end, this gives map/unmap
> 10-40% performance boost (depending on size of mapping) in comparison to
> flushing after each page entry update.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/iommu/tegra-gart.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)

10-40% sounds really nice, great stuff:

Acked-by: Thierry Reding <treding@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index f6cf5cd5aaca..86a855c0d031 100644
--- a/drivers/iommu/tegra-gart.c
+++ b/drivers/iommu/tegra-gart.c
@@ -287,7 +287,6 @@  static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
 		}
 	}
 	gart_set_pte(gart, iova, GART_PTE(pfn));
-	FLUSH_GART_REGS(gart);
 	spin_unlock_irqrestore(&gart->pte_lock, flags);
 	return 0;
 }
@@ -304,7 +303,6 @@  static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 
 	spin_lock_irqsave(&gart->pte_lock, flags);
 	gart_set_pte(gart, iova, 0);
-	FLUSH_GART_REGS(gart);
 	spin_unlock_irqrestore(&gart->pte_lock, flags);
 	return bytes;
 }
@@ -370,6 +368,14 @@  static int gart_iommu_of_xlate(struct device *dev,
 	return 0;
 }
 
+static void gart_iommu_sync(struct iommu_domain *domain)
+{
+	struct gart_domain *gart_domain = to_gart_domain(domain);
+	struct gart_device *gart = gart_domain->gart;
+
+	FLUSH_GART_REGS(gart);
+}
+
 static const struct iommu_ops gart_iommu_ops = {
 	.capable	= gart_iommu_capable,
 	.domain_alloc	= gart_iommu_domain_alloc,
@@ -384,6 +390,8 @@  static const struct iommu_ops gart_iommu_ops = {
 	.iova_to_phys	= gart_iommu_iova_to_phys,
 	.pgsize_bitmap	= GART_IOMMU_PGSIZES,
 	.of_xlate	= gart_iommu_of_xlate,
+	.iotlb_sync_map	= gart_iommu_sync,
+	.iotlb_sync	= gart_iommu_sync,
 };
 
 static int tegra_gart_suspend(struct device *dev)