Am 20.07.2017 um 16:59 schrieb Marek Olšák:


On Jul 19, 2017 10:21 PM, "zhoucm1" <david1.z...@amd.com <mailto:david1.z...@amd.com>> wrote:



    On 2017年07月19日 23:34, Marek Olšák wrote:


    On Jul 19, 2017 3:36 AM, "zhoucm1" <david1.z...@amd.com
    <mailto:david1.z...@amd.com>> wrote:



        On 2017年07月19日 04:08, Marek Olšák wrote:

            From: Marek Olšák <marek.ol...@amd.com
            <mailto:marek.ol...@amd.com>>

            For lower overhead in the CS ioctl.
            Winsys allocators are not used with interprocess-sharable
            resources.

        Hi Marek,

        Could I know from how your this way reduces overhead in CS
        ioctl? reusing BO to short bo list?


    The kernel part of the work hasn't been done yet. The idea is
    that nonsharable buffers don't have to be revalidated by TTM,
    OK, Maybe I only can see the whole picture of this idea when you
    complete kernel part.
    Out of curious,  why/how can nonsharable buffers be revalidated by
    TTM without exposing like amdgpu_bo_make_resident api?


I think the idea is that all nonsharable buffers will be backed by the same reservation object, so TTM can skip buffer validation if no buffer has been moved. It's just an optimization for the current design.


    With mentioned in another thread, if we can expose make_resident
    api, we can remove bo_list, even we can remove reservation
    operation in CS ioctl.


Actually that is NOT a resident api. E.g. in other words BOs marked as this are just swapped out like other BOs.

It's just that on command submission additionally to the BOs which come from the BO list we have the BOs associated to the process as well.

    And now, I think our bo list is a very bad design,
    first, umd must create bo list for every command submission, this
    is a extra cpu overhead compared with traditional way.
    second, kernel also have to iterate the list, when bo list is too
    long, like OpenCL program, they always throw several thousands BOs
    to bo list, reservation must keep these thousands ww_mutex safe,
    CPU overhead is too big.

    So I strongly suggest we should expose make_resident api to user
    space. if cannot, I want to know any specific reason to see if we
    can solve it.


Yeah, I think the BO list idea is likely to die sooner or later. It made sense for GL before bindless was a thing. Nowadays I don't see much value in it.

Completely agree. The BO list API was not a good idea in the first place.

Regards,
Christian.


MesaGL will keep tracking the BO list because it's a requirement for good GL performance (it determines whether to flush IBs before BO synchronization, it allows tracking fences for each BO, which are used to determine dependencies between IBs, and that all allows async SDMA and async compute for GL, which doesn't have separate queues).

However, we don't need any BO list at the libdrm level and lower. I think a BO_CREATE flag that causes that the buffer is added to a kernel-side per-fd BO list would be sufficient. How the kernel manages its BO list should be its own implementation detail. Initially we can just move the current BO list management into the kernel.

Marek





    Regards,
    David Zhou

    so it should remove a lot of kernel overhead and the BO list
    remains the same.

    Marek



        Thanks,
        David Zhou


            v2: It shouldn't crash anymore, but the kernel will
            reject the new flag.
            ---
              src/gallium/drivers/radeon/r600_buffer_common.c |  7 +++++
              src/gallium/drivers/radeon/radeon_winsys.h     | 20
            +++++++++++---
              src/gallium/winsys/amdgpu/drm/amdgpu_bo.c      | 36
            ++++++++++++++++---------
              src/gallium/winsys/radeon/drm/radeon_drm_bo.c  | 27
            +++++++++++--------
              4 files changed, 62 insertions(+), 28 deletions(-)

            diff --git
            a/src/gallium/drivers/radeon/r600_buffer_common.c
            b/src/gallium/drivers/radeon/r600_buffer_common.c
            index dd1c209..2747ac4 100644
            --- a/src/gallium/drivers/radeon/r600_buffer_common.c
            +++ b/src/gallium/drivers/radeon/r600_buffer_common.c
            @@ -160,20 +160,27 @@ void
            r600_init_resource_fields(struct r600_common_screen *rscreen,
                    }
                    /* Tiled textures are unmappable. Always put them
            in VRAM. */
                    if ((res->b.b.target != PIPE_BUFFER &&
            !rtex->surface.is_linear) ||
                        res->flags & R600_RESOURCE_FLAG_UNMAPPABLE) {
                            res->domains = RADEON_DOMAIN_VRAM;
                            res->flags |= RADEON_FLAG_NO_CPU_ACCESS |
             RADEON_FLAG_GTT_WC;
                    }
              +     /* Only displayable single-sample textures can be
            shared between
            +        * processes. */
            +       if (res->b.b.target == PIPE_BUFFER ||
            +           res->b.b.nr_samples >= 2 ||
            +  rtex->surface.micro_tile_mode !=
            RADEON_MICRO_MODE_DISPLAY)
            +               res->flags |=
            RADEON_FLAG_NO_INTERPROCESS_SHARING;
            +
                    /* If VRAM is just stolen system memory, allow
            both VRAM and
                     * GTT, whichever has free space. If a buffer is
            evicted from
                     * VRAM to GTT, it will stay there.
                     *
                     * DRM 3.6.0 has good BO move throttling, so we
            can allow VRAM-only
                     * placements even with a low amount of stolen VRAM.
                     */
                    if (!rscreen->info.has_dedicated_vram &&
            (rscreen->info.drm_major < 3 || rscreen->info.drm_minor <
            6) &&
                        res->domains == RADEON_DOMAIN_VRAM) {
            diff --git a/src/gallium/drivers/radeon/radeon_winsys.h
            b/src/gallium/drivers/radeon/radeon_winsys.h
            index 351edcd..0abcb56 100644
            --- a/src/gallium/drivers/radeon/radeon_winsys.h
            +++ b/src/gallium/drivers/radeon/radeon_winsys.h
            @@ -47,20 +47,21 @@ enum radeon_bo_domain { /* bitfield */
                  RADEON_DOMAIN_GTT  = 2,
                  RADEON_DOMAIN_VRAM = 4,
                  RADEON_DOMAIN_VRAM_GTT = RADEON_DOMAIN_VRAM |
            RADEON_DOMAIN_GTT
              };
                enum radeon_bo_flag { /* bitfield */
                  RADEON_FLAG_GTT_WC =        (1 << 0),
                  RADEON_FLAG_NO_CPU_ACCESS = (1 << 1),
                  RADEON_FLAG_NO_SUBALLOC =   (1 << 2),
                  RADEON_FLAG_SPARSE =        (1 << 3),
            +    RADEON_FLAG_NO_INTERPROCESS_SHARING = (1 << 4),
              };
                enum radeon_bo_usage { /* bitfield */
                  RADEON_USAGE_READ = 2,
                  RADEON_USAGE_WRITE = 4,
                  RADEON_USAGE_READWRITE = RADEON_USAGE_READ |
            RADEON_USAGE_WRITE,
                    /* The winsys ensures that the CS submission will
            be scheduled after
                   * previously flushed CSs referencing this BO in a
            conflicting way.
                   */
            @@ -685,28 +686,33 @@ static inline enum radeon_bo_domain
            radeon_domain_from_heap(enum radeon_heap hea
                  default:
                      assert(0);
                      return (enum radeon_bo_domain)0;
                  }
              }
                static inline unsigned radeon_flags_from_heap(enum
            radeon_heap heap)
              {
                  switch (heap) {
                  case RADEON_HEAP_VRAM_NO_CPU_ACCESS:
            -        return RADEON_FLAG_GTT_WC |
            RADEON_FLAG_NO_CPU_ACCESS;
            +        return RADEON_FLAG_GTT_WC |
            +  RADEON_FLAG_NO_CPU_ACCESS |
            +  RADEON_FLAG_NO_INTERPROCESS_SHARING;
            +
                  case RADEON_HEAP_VRAM:
                  case RADEON_HEAP_VRAM_GTT:
                  case RADEON_HEAP_GTT_WC:
            -        return RADEON_FLAG_GTT_WC;
            +        return RADEON_FLAG_GTT_WC |
            +  RADEON_FLAG_NO_INTERPROCESS_SHARING;
            +
                  case RADEON_HEAP_GTT:
                  default:
            -        return 0;
            +        return RADEON_FLAG_NO_INTERPROCESS_SHARING;
                  }
              }
                /* The pb cache bucket is chosen to minimize pb_cache
            misses.
               * It must be between 0 and 3 inclusive.
               */
              static inline unsigned
            radeon_get_pb_cache_bucket_index(enum radeon_heap heap)
              {
                  switch (heap) {
                  case RADEON_HEAP_VRAM_NO_CPU_ACCESS:
            @@ -724,22 +730,28 @@ static inline unsigned
            radeon_get_pb_cache_bucket_index(enum radeon_heap heap)
                /* Return the heap index for winsys allocators, or -1
            on failure. */
              static inline int radeon_get_heap_index(enum
            radeon_bo_domain domain,
                  enum radeon_bo_flag flags)
              {
                  /* VRAM implies WC (write combining) */
                  assert(!(domain & RADEON_DOMAIN_VRAM) || flags &
            RADEON_FLAG_GTT_WC);
                  /* NO_CPU_ACCESS implies VRAM only. */
                  assert(!(flags & RADEON_FLAG_NO_CPU_ACCESS) ||
            domain == RADEON_DOMAIN_VRAM);
              +    /* Resources with interprocess sharing don't use
            any winsys allocators. */
            +    if (!(flags & RADEON_FLAG_NO_INTERPROCESS_SHARING))
            +        return -1;
            +
                  /* Unsupported flags: NO_SUBALLOC, SPARSE. */
            -    if (flags & ~(RADEON_FLAG_GTT_WC |
            RADEON_FLAG_NO_CPU_ACCESS))
            +    if (flags & ~(RADEON_FLAG_GTT_WC |
            + RADEON_FLAG_NO_CPU_ACCESS |
            + RADEON_FLAG_NO_INTERPROCESS_SHARING))
                      return -1;
                    switch (domain) {
                  case RADEON_DOMAIN_VRAM:
                      if (flags & RADEON_FLAG_NO_CPU_ACCESS)
                          return RADEON_HEAP_VRAM_NO_CPU_ACCESS;
                      else
                          return RADEON_HEAP_VRAM;
                  case RADEON_DOMAIN_VRAM_GTT:
                      return RADEON_HEAP_VRAM_GTT;
            diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
            b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
            index 97bbe23..06b8198 100644
            --- a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
            +++ b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
            @@ -31,20 +31,24 @@
                #include "amdgpu_cs.h"
                #include "os/os_time.h"
              #include "state_tracker/drm_driver.h"
              #include <amdgpu_drm.h>
              #include <xf86drm.h>
              #include <stdio.h>
              #include <inttypes.h>
              +#ifndef AMDGPU_GEM_CREATE_NO_INTERPROCESS_SHARING
            +#define AMDGPU_GEM_CREATE_NO_INTERPROCESS_SHARING (1 << 6)
            +#endif
            +
              /* Set to 1 for verbose output showing committed sparse
            buffer ranges. */
              #define DEBUG_SPARSE_COMMITS 0
                struct amdgpu_sparse_backing_chunk {
                 uint32_t begin, end;
              };
                static struct pb_buffer *
              amdgpu_bo_create(struct radeon_winsys *rws,
                               uint64_t size,
            @@ -395,20 +399,22 @@ static struct amdgpu_winsys_bo
            *amdgpu_create_bo(struct amdgpu_winsys *ws,
                   if (initial_domain & RADEON_DOMAIN_VRAM)
                    request.preferred_heap |= AMDGPU_GEM_DOMAIN_VRAM;
                 if (initial_domain & RADEON_DOMAIN_GTT)
                    request.preferred_heap |= AMDGPU_GEM_DOMAIN_GTT;
                   if (flags & RADEON_FLAG_NO_CPU_ACCESS)
                    request.flags |= AMDGPU_GEM_CREATE_NO_CPU_ACCESS;
                 if (flags & RADEON_FLAG_GTT_WC)
                    request.flags |= AMDGPU_GEM_CREATE_CPU_GTT_USWC;
            +   if (flags & RADEON_FLAG_NO_INTERPROCESS_SHARING)
            +      request.flags |=
            AMDGPU_GEM_CREATE_NO_INTERPROCESS_SHARING;
                   r = amdgpu_bo_alloc(ws->dev, &request, &buf_handle);
                 if (r) {
                    fprintf(stderr, "amdgpu: Failed to allocate a
            buffer:\n");
                    fprintf(stderr, "amdgpu: size      : %"PRIu64"
            bytes\n", size);
                    fprintf(stderr, "amdgpu: alignment : %u bytes\n",
            alignment);
                    fprintf(stderr, "amdgpu: domains   : %u\n",
            initial_domain);
                    goto error_bo_alloc;
                 }
              @@ -1127,21 +1133,21 @@ static void
            amdgpu_buffer_set_metadata(struct pb_buffer *_buf,
                static struct pb_buffer *
              amdgpu_bo_create(struct radeon_winsys *rws,
                               uint64_t size,
                               unsigned alignment,
                               enum radeon_bo_domain domain,
                               enum radeon_bo_flag flags)
              {
                 struct amdgpu_winsys *ws = amdgpu_winsys(rws);
                 struct amdgpu_winsys_bo *bo;
            -   unsigned usage = 0, pb_cache_bucket;
            +   unsigned usage = 0, pb_cache_bucket = 0;
                   /* VRAM implies WC. This is not optional. */
                 assert(!(domain & RADEON_DOMAIN_VRAM) || flags &
            RADEON_FLAG_GTT_WC);
                   /* NO_CPU_ACCESS is valid with VRAM only. */
                 assert(domain == RADEON_DOMAIN_VRAM || !(flags &
            RADEON_FLAG_NO_CPU_ACCESS));
                   /* Sub-allocate small buffers from slabs. */
                 if (!(flags & (RADEON_FLAG_NO_SUBALLOC |
            RADEON_FLAG_SPARSE)) &&
                     size <= (1 << AMDGPU_SLAB_MAX_SIZE_LOG2) &&
            @@ -1182,48 +1188,52 @@ no_slab:
                 /* This flag is irrelevant for the cache. */
                 flags &= ~RADEON_FLAG_NO_SUBALLOC;
                   /* Align size to page size. This is the minimum
            alignment for normal
                  * BOs. Aligning this here helps the cached bufmgr.
            Especially small BOs,
                  * like constant/uniform buffers, can benefit from
            better and more reuse.
                  */
                 size = align64(size, ws->info.gart_page_size);
                 alignment = align(alignment, ws->info.gart_page_size);
              -   int heap = radeon_get_heap_index(domain, flags);
            -   assert(heap >= 0 && heap < RADEON_MAX_CACHED_HEAPS);
            -   usage = 1 << heap; /* Only set one usage bit for each
            heap. */
            +   bool use_reusable_pool = flags &
            RADEON_FLAG_NO_INTERPROCESS_SHARING;
              -   pb_cache_bucket =
            radeon_get_pb_cache_bucket_index(heap);
            -   assert(pb_cache_bucket <
            ARRAY_SIZE(ws->bo_cache.buckets));
            +   if (use_reusable_pool) {
            +       int heap = radeon_get_heap_index(domain, flags);
            +       assert(heap >= 0 && heap < RADEON_MAX_CACHED_HEAPS);
            +       usage = 1 << heap; /* Only set one usage bit for
            each heap. */
              -   /* Get a buffer from the cache. */
            -   bo = (struct amdgpu_winsys_bo*)
            - pb_cache_reclaim_buffer(&ws->bo_cache, size, alignment,
            usage,
            - pb_cache_bucket);
            -   if (bo)
            -      return &bo->base;
            +       pb_cache_bucket =
            radeon_get_pb_cache_bucket_index(heap);
            +       assert(pb_cache_bucket <
            ARRAY_SIZE(ws->bo_cache.buckets));
            +
            +       /* Get a buffer from the cache. */
            +       bo = (struct amdgpu_winsys_bo*)
            + pb_cache_reclaim_buffer(&ws->bo_cache, size, alignment,
            usage,
            + pb_cache_bucket);
            +       if (bo)
            +          return &bo->base;
            +   }
                   /* Create a new one. */
                 bo = amdgpu_create_bo(ws, size, alignment, usage,
            domain, flags,
             pb_cache_bucket);
                 if (!bo) {
                    /* Clear the cache and try again. */
            pb_slabs_reclaim(&ws->bo_slabs);
            pb_cache_release_all_buffers(&ws->bo_cache);
                    bo = amdgpu_create_bo(ws, size, alignment, usage,
            domain, flags,
            pb_cache_bucket);
                    if (!bo)
                       return NULL;
                 }
              -  bo->u.real.use_reusable_pool = true;
            +   bo->u.real.use_reusable_pool = use_reusable_pool;
                 return &bo->base;
              }
                static struct pb_buffer *amdgpu_bo_from_handle(struct
            radeon_winsys *rws,
                         struct winsys_handle *whandle,
                         unsigned *stride,
                         unsigned *offset)
              {
                 struct amdgpu_winsys *ws = amdgpu_winsys(rws);
                 struct amdgpu_winsys_bo *bo;
            diff --git
            a/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
            b/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
            index 8027a5f..15e9d38 100644
            --- a/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
            +++ b/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
            @@ -907,21 +907,21 @@ static void
            radeon_bo_set_metadata(struct pb_buffer *_buf,
                static struct pb_buffer *
              radeon_winsys_bo_create(struct radeon_winsys *rws,
                                      uint64_t size,
                                      unsigned alignment,
                                      enum radeon_bo_domain domain,
                                      enum radeon_bo_flag flags)
              {
                  struct radeon_drm_winsys *ws = radeon_drm_winsys(rws);
                  struct radeon_bo *bo;
            -    unsigned usage = 0, pb_cache_bucket;
            +    unsigned usage = 0, pb_cache_bucket = 0;
                    assert(!(flags & RADEON_FLAG_SPARSE)); /* not
            supported */
                    /* Only 32-bit sizes are supported. */
                  if (size > UINT_MAX)
                      return NULL;
                    /* VRAM implies WC. This is not optional. */
                  if (domain & RADEON_DOMAIN_VRAM)
                      flags |= RADEON_FLAG_GTT_WC;
            @@ -962,46 +962,51 @@ no_slab:
                  /* This flag is irrelevant for the cache. */
                  flags &= ~RADEON_FLAG_NO_SUBALLOC;
                    /* Align size to page size. This is the minimum
            alignment for normal
                   * BOs. Aligning this here helps the cached bufmgr.
            Especially small BOs,
                   * like constant/uniform buffers, can benefit from
            better and more reuse.
                   */
                  size = align(size, ws->info.gart_page_size);
                  alignment = align(alignment, ws->info.gart_page_size);
              -    int heap = radeon_get_heap_index(domain, flags);
            -    assert(heap >= 0 && heap < RADEON_MAX_CACHED_HEAPS);
            -    usage = 1 << heap; /* Only set one usage bit for
            each heap. */
            +    bool use_reusable_pool = flags &
            RADEON_FLAG_NO_INTERPROCESS_SHARING;
              -    pb_cache_bucket =
            radeon_get_pb_cache_bucket_index(heap);
            -    assert(pb_cache_bucket <
            ARRAY_SIZE(ws->bo_cache.buckets));
            +    /* Shared resources don't use cached heaps. */
            +    if (use_reusable_pool) {
            +        int heap = radeon_get_heap_index(domain, flags);
            +        assert(heap >= 0 && heap < RADEON_MAX_CACHED_HEAPS);
            +        usage = 1 << heap; /* Only set one usage bit for
            each heap. */
              -    bo =
            radeon_bo(pb_cache_reclaim_buffer(&ws->bo_cache, size,
            alignment,
            -        usage, pb_cache_bucket));
            -    if (bo)
            -        return &bo->base;
            +        pb_cache_bucket =
            radeon_get_pb_cache_bucket_index(heap);
            +        assert(pb_cache_bucket <
            ARRAY_SIZE(ws->bo_cache.buckets));
            +
            +        bo =
            radeon_bo(pb_cache_reclaim_buffer(&ws->bo_cache, size,
            alignment,
            +            usage, pb_cache_bucket));
            +        if (bo)
            +            return &bo->base;
            +    }
                    bo = radeon_create_bo(ws, size, alignment, usage,
            domain, flags,
            pb_cache_bucket);
                  if (!bo) {
                      /* Clear the cache and try again. */
                      if (ws->info.has_virtual_memory)
            pb_slabs_reclaim(&ws->bo_slabs);
            pb_cache_release_all_buffers(&ws->bo_cache);
                      bo = radeon_create_bo(ws, size, alignment,
            usage, domain, flags,
            pb_cache_bucket);
                      if (!bo)
                          return NULL;
                  }
              - bo->u.real.use_reusable_pool = true;
            +    bo->u.real.use_reusable_pool = use_reusable_pool;
            mtx_lock(&ws->bo_handles_mutex);
            util_hash_table_set(ws->bo_handles,
            (void*)(uintptr_t)bo->handle, bo);
            mtx_unlock(&ws->bo_handles_mutex);
                    return &bo->base;
              }
                static struct pb_buffer
            *radeon_winsys_bo_from_ptr(struct radeon_winsys *rws,
                             void *pointer, uint64_t size)







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