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sparc: Make sparc64 use scalable lib/iommu-common.c functions

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In iperf experiments running linux as the Tx side (TCP client) with
10 threads results in a severe performance drop when TSO is disabled,
indicating a weakness in the software that can be avoided by using
the scalable IOMMU arena DMA allocation.

Baseline numbers before this patch:
   with default settings (TSO enabled) :    9-9.5 Gbps
   Disable TSO using ethtool- drops badly:  2-3 Gbps.

After this patch, iperf client with 10 threads, can give a
throughput of at least 8.5 Gbps, even when TSO is disabled.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sowmini Varadhan
2015-04-09 15:33:31 -04:00
committed by David S. Miller
parent ff7d37a502
commit bb620c3d39
4 changed files with 127 additions and 241 deletions
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7
arch/sparc/include/asm/iommu_64.h
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@@ -16,6 +16,7 @@
#define IOPTE_WRITE 0x0000000000000002UL
#define IOMMU_NUM_CTXS 4096
#include <linux/iommu-common.h>
struct iommu_arena {
unsigned long *map;
@@ -24,11 +25,10 @@ struct iommu_arena {
};
struct iommu {
struct iommu_map_table tbl;
spinlock_t lock;
struct iommu_arena arena;
void (*flush_all)(struct iommu *);
u32 dma_addr_mask;
iopte_t *page_table;
u32 page_table_map_base;
unsigned long iommu_control;
unsigned long iommu_tsbbase;
unsigned long iommu_flush;
@@ -40,7 +40,6 @@ struct iommu {
unsigned long dummy_page_pa;
unsigned long ctx_lowest_free;
DECLARE_BITMAP(ctx_bitmap, IOMMU_NUM_CTXS);
u32 dma_addr_mask;
};
struct strbuf {