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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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bb620c3d39
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>
65 lines
1.8 KiB
C
65 lines
1.8 KiB
C
/* iommu.h: Definitions for the sun5 IOMMU.
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*
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* Copyright (C) 1996, 1999, 2007 David S. Miller (davem@davemloft.net)
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*/
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#ifndef _SPARC64_IOMMU_H
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#define _SPARC64_IOMMU_H
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/* The format of an iopte in the page tables. */
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#define IOPTE_VALID 0x8000000000000000UL
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#define IOPTE_64K 0x2000000000000000UL
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#define IOPTE_STBUF 0x1000000000000000UL
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#define IOPTE_INTRA 0x0800000000000000UL
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#define IOPTE_CONTEXT 0x07ff800000000000UL
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#define IOPTE_PAGE 0x00007fffffffe000UL
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#define IOPTE_CACHE 0x0000000000000010UL
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#define IOPTE_WRITE 0x0000000000000002UL
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#define IOMMU_NUM_CTXS 4096
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#include <linux/iommu-common.h>
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struct iommu_arena {
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unsigned long *map;
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unsigned int hint;
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unsigned int limit;
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};
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struct iommu {
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struct iommu_map_table tbl;
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spinlock_t lock;
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u32 dma_addr_mask;
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iopte_t *page_table;
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unsigned long iommu_control;
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unsigned long iommu_tsbbase;
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unsigned long iommu_flush;
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unsigned long iommu_flushinv;
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unsigned long iommu_tags;
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unsigned long iommu_ctxflush;
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unsigned long write_complete_reg;
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unsigned long dummy_page;
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unsigned long dummy_page_pa;
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unsigned long ctx_lowest_free;
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DECLARE_BITMAP(ctx_bitmap, IOMMU_NUM_CTXS);
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};
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struct strbuf {
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int strbuf_enabled;
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unsigned long strbuf_control;
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unsigned long strbuf_pflush;
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unsigned long strbuf_fsync;
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unsigned long strbuf_err_stat;
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unsigned long strbuf_tag_diag;
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unsigned long strbuf_line_diag;
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unsigned long strbuf_ctxflush;
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unsigned long strbuf_ctxmatch_base;
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unsigned long strbuf_flushflag_pa;
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volatile unsigned long *strbuf_flushflag;
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volatile unsigned long __flushflag_buf[(64+(64-1)) / sizeof(long)];
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};
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int iommu_table_init(struct iommu *iommu, int tsbsize,
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u32 dma_offset, u32 dma_addr_mask,
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int numa_node);
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#endif /* !(_SPARC64_IOMMU_H) */
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