[PATCH 1/2] drm/radeon: add large PTE support for NI, SI and CIK v5

Alex Deucher alexdeucher at gmail.com
Mon May 19 07:35:10 PDT 2014


On Sat, May 10, 2014 at 6:17 AM, Christian König
<deathsimple at vodafone.de> wrote:
> From: Christian König <christian.koenig at amd.com>
>
> This patch implements support for VRAM page table entry compression.
> PTE construction is enhanced to identify physically contiguous page
> ranges and mark them in the PTE fragment field. L1/L2 TLB support is
> enabled for 64KB (SI/CIK) and 256KB (NI) PTE fragments, significantly
> improving TLB utilization for VRAM allocations.
>
> Linear store bandwidth is improved from 60GB/s to 125GB/s on Pitcairn.
> Unigine Heaven 3.0 sees an average improvement from 24.7 to 27.7 FPS
> on default settings at 1920x1200 resolution with vsync disabled.
>
> See main comment in radeon_vm.c for a technical description.
>
> v2 (chk): rebased and simplified.
> v3 (chk): add missing hw setup
> v4 (chk): rebased on current drm-fixes-3.15
> v5 (chk): fix comments and commit text
>
> Signed-off-by: Jay Cornwall <jay at jcornwall.me>
> Signed-off-by: Christian König <christian.koenig at amd.com>

Applied both to my 3.16 tree.

Thanks!

Alex

> ---
>  drivers/gpu/drm/radeon/cik.c       |  4 +-
>  drivers/gpu/drm/radeon/ni.c        |  2 +
>  drivers/gpu/drm/radeon/radeon.h    |  5 +++
>  drivers/gpu/drm/radeon/radeon_vm.c | 91 +++++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/radeon/si.c        |  5 ++-
>  5 files changed, 98 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
> index 5143e0b..ce26b2a 100644
> --- a/drivers/gpu/drm/radeon/cik.c
> +++ b/drivers/gpu/drm/radeon/cik.c
> @@ -5329,6 +5329,7 @@ static int cik_pcie_gart_enable(struct radeon_device *rdev)
>         WREG32(MC_VM_MX_L1_TLB_CNTL,
>                (0xA << 7) |
>                ENABLE_L1_TLB |
> +              ENABLE_L1_FRAGMENT_PROCESSING |
>                SYSTEM_ACCESS_MODE_NOT_IN_SYS |
>                ENABLE_ADVANCED_DRIVER_MODEL |
>                SYSTEM_APERTURE_UNMAPPED_ACCESS_PASS_THRU);
> @@ -5341,7 +5342,8 @@ static int cik_pcie_gart_enable(struct radeon_device *rdev)
>                CONTEXT1_IDENTITY_ACCESS_MODE(1));
>         WREG32(VM_L2_CNTL2, INVALIDATE_ALL_L1_TLBS | INVALIDATE_L2_CACHE);
>         WREG32(VM_L2_CNTL3, L2_CACHE_BIGK_ASSOCIATIVITY |
> -              L2_CACHE_BIGK_FRAGMENT_SIZE(6));
> +              BANK_SELECT(4) |
> +              L2_CACHE_BIGK_FRAGMENT_SIZE(4));
>         /* setup context0 */
>         WREG32(VM_CONTEXT0_PAGE_TABLE_START_ADDR, rdev->mc.gtt_start >> 12);
>         WREG32(VM_CONTEXT0_PAGE_TABLE_END_ADDR, rdev->mc.gtt_end >> 12);
> diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
> index d246e04..5e8db9b 100644
> --- a/drivers/gpu/drm/radeon/ni.c
> +++ b/drivers/gpu/drm/radeon/ni.c
> @@ -1228,12 +1228,14 @@ static int cayman_pcie_gart_enable(struct radeon_device *rdev)
>                SYSTEM_APERTURE_UNMAPPED_ACCESS_PASS_THRU);
>         /* Setup L2 cache */
>         WREG32(VM_L2_CNTL, ENABLE_L2_CACHE |
> +              ENABLE_L2_FRAGMENT_PROCESSING |
>                ENABLE_L2_PTE_CACHE_LRU_UPDATE_BY_WRITE |
>                ENABLE_L2_PDE0_CACHE_LRU_UPDATE_BY_WRITE |
>                EFFECTIVE_L2_QUEUE_SIZE(7) |
>                CONTEXT1_IDENTITY_ACCESS_MODE(1));
>         WREG32(VM_L2_CNTL2, INVALIDATE_ALL_L1_TLBS | INVALIDATE_L2_CACHE);
>         WREG32(VM_L2_CNTL3, L2_CACHE_BIGK_ASSOCIATIVITY |
> +              BANK_SELECT(6) |
>                L2_CACHE_BIGK_FRAGMENT_SIZE(6));
>         /* setup context0 */
>         WREG32(VM_CONTEXT0_PAGE_TABLE_START_ADDR, rdev->mc.gtt_start >> 12);
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index 91be3d6..5c4742c 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -854,6 +854,11 @@ struct radeon_mec {
>  #define R600_PTE_READABLE      (1 << 5)
>  #define R600_PTE_WRITEABLE     (1 << 6)
>
> +/* PTE (Page Table Entry) fragment field for different page sizes */
> +#define R600_PTE_FRAG_4KB      (0 << 7)
> +#define R600_PTE_FRAG_64KB     (4 << 7)
> +#define R600_PTE_FRAG_256KB    (6 << 7)
> +
>  struct radeon_vm_pt {
>         struct radeon_bo                *bo;
>         uint64_t                        addr;
> diff --git a/drivers/gpu/drm/radeon/radeon_vm.c b/drivers/gpu/drm/radeon/radeon_vm.c
> index 2aae6ce..f8d5b65 100644
> --- a/drivers/gpu/drm/radeon/radeon_vm.c
> +++ b/drivers/gpu/drm/radeon/radeon_vm.c
> @@ -658,6 +658,84 @@ int radeon_vm_update_page_directory(struct radeon_device *rdev,
>  }
>
>  /**
> + * radeon_vm_frag_ptes - add fragment information to PTEs
> + *
> + * @rdev: radeon_device pointer
> + * @ib: IB for the update
> + * @pe_start: first PTE to handle
> + * @pe_end: last PTE to handle
> + * @addr: addr those PTEs should point to
> + * @flags: hw mapping flags
> + *
> + * Global and local mutex must be locked!
> + */
> +static void radeon_vm_frag_ptes(struct radeon_device *rdev,
> +                               struct radeon_ib *ib,
> +                               uint64_t pe_start, uint64_t pe_end,
> +                               uint64_t addr, uint32_t flags)
> +{
> +       /**
> +        * The MC L1 TLB supports variable sized pages, based on a fragment
> +        * field in the PTE. When this field is set to a non-zero value, page
> +        * granularity is increased from 4KB to (1 << (12 + frag)). The PTE
> +        * flags are considered valid for all PTEs within the fragment range
> +        * and corresponding mappings are assumed to be physically contiguous.
> +        *
> +        * The L1 TLB can store a single PTE for the whole fragment,
> +        * significantly increasing the space available for translation
> +        * caching. This leads to large improvements in throughput when the
> +        * TLB is under pressure.
> +        *
> +        * The L2 TLB distributes small and large fragments into two
> +        * asymmetric partitions. The large fragment cache is significantly
> +        * larger. Thus, we try to use large fragments wherever possible.
> +        * Userspace can support this by aligning virtual base address and
> +        * allocation size to the fragment size.
> +        */
> +
> +       /* NI is optimized for 256KB fragments, SI and newer for 64KB */
> +       uint64_t frag_flags = rdev->family == CHIP_CAYMAN ?
> +                       R600_PTE_FRAG_256KB : R600_PTE_FRAG_64KB;
> +       uint64_t frag_align = rdev->family == CHIP_CAYMAN ? 0x200 : 0x80;
> +
> +       uint64_t frag_start = ALIGN(pe_start, frag_align);
> +       uint64_t frag_end = pe_end & ~(frag_align - 1);
> +
> +       unsigned count;
> +
> +       /* system pages are non continuously */
> +       if ((flags & R600_PTE_SYSTEM) || !(flags & R600_PTE_VALID) ||
> +           (frag_start >= frag_end)) {
> +
> +               count = (pe_end - pe_start) / 8;
> +               radeon_asic_vm_set_page(rdev, ib, pe_start, addr, count,
> +                                       RADEON_GPU_PAGE_SIZE, flags);
> +               return;
> +       }
> +
> +       /* handle the 4K area at the beginning */
> +       if (pe_start != frag_start) {
> +               count = (frag_start - pe_start) / 8;
> +               radeon_asic_vm_set_page(rdev, ib, pe_start, addr, count,
> +                                       RADEON_GPU_PAGE_SIZE, flags);
> +               addr += RADEON_GPU_PAGE_SIZE * count;
> +       }
> +
> +       /* handle the area in the middle */
> +       count = (frag_end - frag_start) / 8;
> +       radeon_asic_vm_set_page(rdev, ib, frag_start, addr, count,
> +                               RADEON_GPU_PAGE_SIZE, flags | frag_flags);
> +
> +       /* handle the 4K area at the end */
> +       if (frag_end != pe_end) {
> +               addr += RADEON_GPU_PAGE_SIZE * count;
> +               count = (pe_end - frag_end) / 8;
> +               radeon_asic_vm_set_page(rdev, ib, frag_end, addr, count,
> +                                       RADEON_GPU_PAGE_SIZE, flags);
> +       }
> +}
> +
> +/**
>   * radeon_vm_update_ptes - make sure that page tables are valid
>   *
>   * @rdev: radeon_device pointer
> @@ -703,10 +781,9 @@ static void radeon_vm_update_ptes(struct radeon_device *rdev,
>                 if ((last_pte + 8 * count) != pte) {
>
>                         if (count) {
> -                               radeon_asic_vm_set_page(rdev, ib, last_pte,
> -                                                       last_dst, count,
> -                                                       RADEON_GPU_PAGE_SIZE,
> -                                                       flags);
> +                               radeon_vm_frag_ptes(rdev, ib, last_pte,
> +                                                   last_pte + 8 * count,
> +                                                   last_dst, flags);
>                         }
>
>                         count = nptes;
> @@ -721,9 +798,9 @@ static void radeon_vm_update_ptes(struct radeon_device *rdev,
>         }
>
>         if (count) {
> -               radeon_asic_vm_set_page(rdev, ib, last_pte,
> -                                       last_dst, count,
> -                                       RADEON_GPU_PAGE_SIZE, flags);
> +               radeon_vm_frag_ptes(rdev, ib, last_pte,
> +                                   last_pte + 8 * count,
> +                                   last_dst, flags);
>         }
>  }
>
> diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
> index 22a63c9..dece3be 100644
> --- a/drivers/gpu/drm/radeon/si.c
> +++ b/drivers/gpu/drm/radeon/si.c
> @@ -4044,18 +4044,21 @@ static int si_pcie_gart_enable(struct radeon_device *rdev)
>         WREG32(MC_VM_MX_L1_TLB_CNTL,
>                (0xA << 7) |
>                ENABLE_L1_TLB |
> +              ENABLE_L1_FRAGMENT_PROCESSING |
>                SYSTEM_ACCESS_MODE_NOT_IN_SYS |
>                ENABLE_ADVANCED_DRIVER_MODEL |
>                SYSTEM_APERTURE_UNMAPPED_ACCESS_PASS_THRU);
>         /* Setup L2 cache */
>         WREG32(VM_L2_CNTL, ENABLE_L2_CACHE |
> +              ENABLE_L2_FRAGMENT_PROCESSING |
>                ENABLE_L2_PTE_CACHE_LRU_UPDATE_BY_WRITE |
>                ENABLE_L2_PDE0_CACHE_LRU_UPDATE_BY_WRITE |
>                EFFECTIVE_L2_QUEUE_SIZE(7) |
>                CONTEXT1_IDENTITY_ACCESS_MODE(1));
>         WREG32(VM_L2_CNTL2, INVALIDATE_ALL_L1_TLBS | INVALIDATE_L2_CACHE);
>         WREG32(VM_L2_CNTL3, L2_CACHE_BIGK_ASSOCIATIVITY |
> -              L2_CACHE_BIGK_FRAGMENT_SIZE(0));
> +              BANK_SELECT(4) |
> +              L2_CACHE_BIGK_FRAGMENT_SIZE(4));
>         /* setup context0 */
>         WREG32(VM_CONTEXT0_PAGE_TABLE_START_ADDR, rdev->mc.gtt_start >> 12);
>         WREG32(VM_CONTEXT0_PAGE_TABLE_END_ADDR, rdev->mc.gtt_end >> 12);
> --
> 1.9.1
>
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