[Beignet] [Beignet 1/3] Add register allocate from tail to support constant buffer.

Yang, Rong R rong.r.yang at intel.com
Wed Apr 17 23:11:37 PDT 2013


Hi, Zhigang,

I have send out the new patches. I will add another test case later.

In my environment, there are no warning message like:
/home/gong/git/fdo/beignet/utests/compiler_function_constant.cpp: In function ‘void compiler_function_constant()’:
/home/gong/git/fdo/beignet/utests/compiler_function_constant.cpp:29:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

I change some variable's type, if there are still this warning in your side, please let me know.

Thanks,
Yang Rong

-----Original Message-----
From: Zhigang Gong [mailto:zhigang.gong at linux.intel.com] 
Sent: Wednesday, April 17, 2013 7:41 PM
To: Yang, Rong R
Cc: beignet at lists.freedesktop.org
Subject: Re: [Beignet] [Beignet 1/3] Add register allocate from tail to support constant buffer.

Nice work! Rong. I tried the patchset, and it works fine.

But the second patch is too large to review. Could you split it to several patches according the following suggestion:

1. Split the compiler side code and the run time library code.
2. Separate those helper functions.
3. Split the change of the register allocation. (change from tail to head.) 4. One separate patch to implement the constant buffer.
5. One separate patch for the kernel recompiling.

And If you can write more test cases, for example, there are more than one constant buffers or a new test case can hit the kernel recompiling code path.

BTW, it seems the patchset has some format issue, next time, please fix those format warnings before your submit it out. You will see the following warnings, if you try to apply those patches.

Applying: Add register allocate from tail to support constant buffer.
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:25: trailing whitespace.
    Block *tail;
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:60: trailing whitespace.

/home/gong/git/fdo/beignet/.git/rebase-apply/patch:80: trailing whitespace.

/home/gong/git/fdo/beignet/.git/rebase-apply/patch:260: trailing whitespace.

/home/gong/git/fdo/beignet/.git/rebase-apply/patch:278: trailing whitespace.

warning: 5 lines add whitespace errors.
Applying: Put constant buffer of argument to payload.
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:55: trailing whitespace.
    }
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:57: trailing whitespace.

/home/gong/git/fdo/beignet/.git/rebase-apply/patch:59: trailing whitespace.
    for (uint32_t argID = 0; argID < kernel->argNum; ++argID) {
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:65: trailing whitespace.
      //free previous
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:70: trailing whitespace.

warning: squelched 29 whitespace errors
warning: 34 lines add whitespace errors.
Applying: Add constant buffer test case.
/home/gong/git/fdo/beignet/.git/rebase-apply/patch:59: trailing whitespace.

/home/gong/git/fdo/beignet/.git/rebase-apply/patch:21: new blank line at EOF.
+
warning: 2 lines add whitespace errors.


/home/gong/git/fdo/beignet/utests/compiler_function_constant.cpp: In function ‘void compiler_function_constant()’:
/home/gong/git/fdo/beignet/utests/compiler_function_constant.cpp:29:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

On Tue, Apr 16, 2013 at 04:48:16PM +0800, Yang Rong wrote:
> By default curbe alloc from head, grf alloc from tail.
> 
> Signed-off-by: Yang Rong <rong.r.yang at intel.com>
> ---
>  backend/src/backend/context.cpp |  190 
> ++++++++++++++++++++++-----------------
>  1 file changed, 108 insertions(+), 82 deletions(-)
> 
> diff --git a/backend/src/backend/context.cpp 
> b/backend/src/backend/context.cpp index 180e8bb..88f704b 100644
> --- a/backend/src/backend/context.cpp
> +++ b/backend/src/backend/context.cpp
> @@ -53,7 +53,7 @@ namespace gbe
>       *  the hardware. Note that we always use the left most block when
>       *  allocating, so it makes sense for constant pushing
>       */
> -    int16_t allocate(int16_t size, int16_t alignment);
> +    int16_t allocate(int16_t size, int16_t alignment, bool bFwd=0);
>  
>      /*! Free the given register file piece */
>      void deallocate(int16_t offset);
> @@ -75,8 +75,9 @@ namespace gbe
>       *  If the colascing was done, the left block is deleted
>       */
>      void coalesce(Block *left, Block *right);
> -    /*! Head of the free list */
> +    /*! Head and tail of the free list */
>      Block *head;
> +    Block *tail;    
>      /*! Handle free list element allocation */
>      DECL_POOL(Block, blockPool);
>      /*! Track allocated memory blocks <offset, size> */ @@ -89,7 
> +90,7 @@ namespace gbe
>      // r0 is always set by the HW and used at the end by EOT
>      const int16_t offset = GEN_REG_SIZE;
>      const int16_t size = RegisterFileSize  - offset;
> -    head = this->newBlock(offset, size);
> +    tail = head = this->newBlock(offset, size);
>    }
>  
>    RegisterFilePartitioner::~RegisterFilePartitioner(void) { @@ 
> -100,80 +101,104 @@ namespace gbe
>      }
>    }
>  
> -  int16_t RegisterFilePartitioner::allocate(int16_t size, int16_t 
> alignment)
> +  int16_t RegisterFilePartitioner::allocate(int16_t size, int16_t 
> + alignment, bool bFwd)
>    {
>      // Make it simple and just use the first block we find
> -    Block *list = head;
> +    Block *list = bFwd ? head : tail;
>      while (list) {
> -      const int16_t aligned = ALIGN(list->offset, alignment);
> -      const int16_t spaceOnLeft = aligned - list->offset;
> -      const int16_t spaceOnRight = list->size - size - spaceOnLeft;
> -
> +      int16_t aligned;
> +      int16_t spaceOnLeft;
> +      int16_t spaceOnRight;
> +      if(bFwd) {
> +        aligned = ALIGN(list->offset, alignment);
> +        spaceOnLeft = aligned - list->offset;
> +        spaceOnRight = list->size - size - spaceOnLeft;
> +      
>        // Not enough space in this block
> -      if (spaceOnRight < 0) {
> -        list = list->next;
> -        continue;
> +        if (spaceOnRight < 0) {
> +          list = list->next;
> +          continue;
> +        }
> +      } else {
> +        aligned = ALIGN(list->offset+list->size-size-(alignment-1), alignment);   //alloc from block's tail
> +        spaceOnLeft = aligned - list->offset;
> +        spaceOnRight = list->size - size - spaceOnLeft;
> +
> +        // Not enough space in this block
> +        if (spaceOnLeft < 0) {
> +          list = list->prev;
> +          continue;
> +        }
>        }
> +      
>        // Cool we can use this block
> -      else {
> -        Block *left = list->prev;
> -        Block *right = list->next;
> -
> -        // If we left a hole on the left, create a new block
> -        if (spaceOnLeft) {
> -          Block *newBlock = this->newBlock(list->offset, spaceOnLeft);
> -          if (left) {
> -            left->next = newBlock;
> -            newBlock->prev = left;
> -          }
> -          if (right) {
> -            newBlock->next = right;
> -            right->prev = newBlock;
> -          }
> -          left = newBlock;
> +      Block *left = list->prev;
> +      Block *right = list->next;
> +
> +      // If we left a hole on the left, create a new block
> +      if (spaceOnLeft) {
> +        Block *newBlock = this->newBlock(list->offset, spaceOnLeft);
> +        if (left) {
> +          left->next = newBlock;
> +          newBlock->prev = left;
>          }
> -
> -        // If we left a hole on the right, create a new block as well
> -        if (spaceOnRight) {
> -          Block *newBlock = this->newBlock(aligned + size, spaceOnRight);
> -          if (left) {
> -            left->next = newBlock;
> -            newBlock->prev = left;
> -          }
> -          if (right) {
> -            right->prev = newBlock;
> -            newBlock->next = right;
> -          }
> -          right = newBlock;
> +        if (right) {
> +          newBlock->next = right;
> +          right->prev = newBlock;
>          }
> +        left = newBlock;
> +      }
>  
> -        // Chain both successors and predecessors when the entire block was
> -        // allocated
> -        if (spaceOnLeft == 0 && spaceOnRight == 0) {
> -          if (left) left->next = right;
> -          if (right) right->prev = left;
> +      // If we left a hole on the right, create a new block as well
> +      if (spaceOnRight) {
> +        Block *newBlock = this->newBlock(aligned + size, spaceOnRight);
> +        if (left) {
> +          left->next = newBlock;
> +          newBlock->prev = left;
>          }
> -
> -        // Update the head of the free blocks
> -        if (list == head) {
> -          if (left)
> -            head = left;
> -          else if (right)
> -            head = right;
> -          else
> -            head = NULL;
> +        if (right) {
> +          right->prev = newBlock;
> +          newBlock->next = right;
>          }
> +        right = newBlock;
> +      }
>  
> -        // Free the block and check the consistency
> -        this->deleteBlock(list);
> -        if (head && head->next) GBE_ASSERT(head->next->prev == head);
> +      // Chain both successors and predecessors when the entire block was
> +      // allocated
> +      if (spaceOnLeft == 0 && spaceOnRight == 0) {
> +        if (left) left->next = right;
> +        if (right) right->prev = left;
> +      }
>  
> -        // Track the allocation to retrieve the size later
> -        allocatedBlocks.insert(std::make_pair(aligned, size));
> +      // Update the head of the free blocks
> +      if (list == head) {
> +        if (left)
> +          head = left;
> +        else if (right)
> +          head = right;
> +        else
> +          head = NULL;
> +      }
>  
> -        // We have a valid offset now
> -        return aligned;
> +      // Update the tail of the free blocks
> +      if (list == tail) {
> +        if (right)
> +          tail = right;
> +        else if (left)
> +          tail = left;
> +        else
> +          tail = NULL;
>        }
> +      // Free the block and check the consistency
> +      this->deleteBlock(list);
> +      if (head && head->next) GBE_ASSERT(head->next->prev == head);
> +      if (tail && tail->prev) GBE_ASSERT(tail->prev->next == tail);
> +
> +      // Track the allocation to retrieve the size later
> +      allocatedBlocks.insert(std::make_pair(aligned, size));
> +
> +      // We have a valid offset now
> +      return aligned;
>      }
>      return 0;
>    }
> @@ -186,34 +211,35 @@ namespace gbe
>      const int16_t size = it->second;
>  
>      // Find the two blocks where to insert the new block
> -    Block *list = head, *prev = NULL;
> +    Block *list = tail, *next = NULL;
>      while (list != NULL) {
> -      if (list->offset > offset)
> +      if (list->offset < offset)
>          break;
> -      prev = list;
> -      list = list->next;
> +      next = list;
> +      list = list->prev;
>      }
>  
>      // Create the block and insert it
>      Block *newBlock = this->newBlock(offset, size);
> -    if (prev) {
> -      GBE_ASSERT(prev->offset + prev->size <= offset);
> -      prev->next = newBlock;
> -      newBlock->prev = prev;
> +    if (list) {
> +      GBE_ASSERT(list->offset + list->size <= offset);
> +      list->next = newBlock;
> +      newBlock->prev = list;
>      } else
> -      this->head = newBlock;  // prev is NULL means newBlock should be the head.
> +      this->head = newBlock;  // list is NULL means newBlock should be the head.
>  
> -    if (list) {
> -      GBE_ASSERT(offset + size <= list->offset);
> -      list->prev = newBlock;
> -      newBlock->next = list;
> -    }
> +    if (next) {
> +      GBE_ASSERT(offset + size <= next->offset);
> +      next->prev = newBlock;
> +      newBlock->next = next;
> +    } else
> +      this->tail = newBlock;  // next is NULL means newBlock should be the tail.
>  
> -    if (prev != NULL || list != NULL)
> +    if (list != NULL || next != NULL)
>      {
>        // Coalesce the blocks if possible
> -      this->coalesce(prev, newBlock);
> -      this->coalesce(newBlock, list);
> +      this->coalesce(list, newBlock);
> +      this->coalesce(newBlock, next);
>      }
>  
>      // Do not track this allocation anymore @@ -275,7 +301,7 @@ 
> namespace gbe
>      }
>      return this->kernel;
>    }
> -
> +  
>    int16_t Context::allocate(int16_t size, int16_t alignment) {
>      return partitioner->allocate(size, alignment);
>    }
> @@ -297,7 +323,7 @@ namespace gbe
>                                uint32_t alignment)
>    {
>      alignment = alignment == 0 ? size : alignment;
> -    const uint32_t offset = partitioner->allocate(size, alignment);
> +    const uint32_t offset = partitioner->allocate(size, alignment, 
> + 1);
>      GBE_ASSERT(offset >= GEN_REG_SIZE);
>      kernel->patches.push_back(PatchInfo(value, subValue, offset - GEN_REG_SIZE));
>      kernel->curbeSize = std::max(kernel->curbeSize, offset + size - 
> GEN_REG_SIZE); @@ -521,7 +547,7 @@ namespace gbe
>      const bool useSLM = fn.getUseSLM();
>      kernel->useSLM = useSLM;
>    }
> -
> +  
>    bool Context::isScalarReg(const ir::Register &reg) const {
>      GBE_ASSERT(fn.getProfile() == ir::Profile::PROFILE_OCL);
>      if (fn.getArg(reg) != NULL) return true;
> --
> 1.7.9.5
> 
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