Split VAO dirty bits to speed iteration.

Using > 64 bits (we had over 90) would use a much slower dirty bit
iteration. Speed this up by splitting the dirty bits into two levels.
The first top level only has a single dirty bit per attrib, per
binding, and one bit for the element array buffer. The next level has
separate dirty bits for attribs and bindings.

The D3D11 back-end doesn't actually care about individual dirty bits
of attribs or bindings, since it resets entire attributes at a time,
but the GL back-end only refreshes the necessary info.

Improves the score of a simple state change microbenchmark by 15% on
the D3D11 and GL back-ends with a no-op driver. Real-world impact will
be smaller.

Also includes a test suppression for an NVIDIA bug that surfaced when
we changed the order of that GL commands were sent to the driver.

BUG=angleproject:2389

Change-Id: If8d5e5eb0b27e2a77e20535e33626183d372d311
Reviewed-on: https://chromium-review.googlesource.com/556799
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>

src/libANGLE/VertexArray.cpp

@@ -111,7 +111,19 @@ size_t VertexArray::GetVertexIndexFromDirtyBit(size_t dirtyBit)
     static_assert(gl::MAX_VERTEX_ATTRIBS == gl::MAX_VERTEX_ATTRIB_BINDINGS,
                   "The stride of vertex attributes should equal to that of vertex bindings.");
     ASSERT(dirtyBit > DIRTY_BIT_ELEMENT_ARRAY_BUFFER);
-    return (dirtyBit - DIRTY_BIT_ATTRIB_0_ENABLED) % gl::MAX_VERTEX_ATTRIBS;
+    return (dirtyBit - DIRTY_BIT_ATTRIB_0) % gl::MAX_VERTEX_ATTRIBS;
+}
+
+void VertexArray::setDirtyAttribBit(size_t attribIndex, DirtyAttribBitType dirtyAttribBit)
+{
+    mDirtyBits.set(DIRTY_BIT_ATTRIB_0 + attribIndex);
+    mDirtyAttribBits[attribIndex].set(dirtyAttribBit);
+}
+
+void VertexArray::setDirtyBindingBit(size_t bindingIndex, DirtyBindingBitType dirtyBindingBit)
+{
+    mDirtyBits.set(DIRTY_BIT_BINDING_0 + bindingIndex);
+    mDirtyBindingBits[bindingIndex].set(dirtyBindingBit);
 }
 
 void VertexArray::bindVertexBufferImpl(const Context *context,
@@ -137,8 +149,7 @@ void VertexArray::bindVertexBuffer(const Context *context,
                                    GLsizei stride)
 {
     bindVertexBufferImpl(context, bindingIndex, boundBuffer, offset, stride);
-
-    mDirtyBits.set(DIRTY_BIT_BINDING_0_BUFFER + bindingIndex);
+    setDirtyBindingBit(bindingIndex, DIRTY_BINDING_BUFFER);
 }
 
 void VertexArray::setVertexAttribBinding(const Context *context,
@@ -153,17 +164,17 @@ void VertexArray::setVertexAttribBinding(const Context *context,
         ASSERT(context->getClientVersion() >= ES_3_1);
         mState.mVertexAttributes[attribIndex].bindingIndex = bindingIndex;
 
-        mDirtyBits.set(DIRTY_BIT_ATTRIB_0_BINDING + attribIndex);
+        setDirtyAttribBit(attribIndex, DIRTY_ATTRIB_BINDING);
     }
+    mState.mVertexAttributes[attribIndex].bindingIndex = static_cast<GLuint>(bindingIndex);
 }
 
 void VertexArray::setVertexBindingDivisor(size_t bindingIndex, GLuint divisor)
 {
     ASSERT(bindingIndex < getMaxBindings());
 
     mState.mVertexBindings[bindingIndex].setDivisor(divisor);
-
-    mDirtyBits.set(DIRTY_BIT_BINDING_0_DIVISOR + bindingIndex);
+    setDirtyBindingBit(bindingIndex, DIRTY_BINDING_DIVISOR);
 }
 
 void VertexArray::setVertexAttribFormatImpl(size_t attribIndex,
@@ -194,8 +205,7 @@ void VertexArray::setVertexAttribFormat(size_t attribIndex,
                                         GLuint relativeOffset)
 {
     setVertexAttribFormatImpl(attribIndex, size, type, normalized, pureInteger, relativeOffset);
-
-    mDirtyBits.set(DIRTY_BIT_ATTRIB_0_FORMAT + attribIndex);
+    setDirtyAttribBit(attribIndex, DIRTY_ATTRIB_FORMAT);
 }
 
 void VertexArray::setVertexAttribDivisor(const Context *context, size_t attribIndex, GLuint divisor)
@@ -214,7 +224,7 @@ void VertexArray::enableAttribute(size_t attribIndex, bool enabledState)
     mState.mVertexAttributesTypeMask.setIndex(
         GetVertexAttributeBaseType(mState.mVertexAttributes[attribIndex]), attribIndex);
 
-    mDirtyBits.set(DIRTY_BIT_ATTRIB_0_ENABLED + attribIndex);
+    setDirtyAttribBit(attribIndex, DIRTY_ATTRIB_ENABLED);
 
     // Update state cache
     mState.mEnabledAttributesMask.set(attribIndex, enabledState);
@@ -246,7 +256,7 @@ void VertexArray::setVertexAttribPointer(const Context *context,
 
     bindVertexBufferImpl(context, attribIndex, boundBuffer, offset, effectiveStride);
 
-    mDirtyBits.set(DIRTY_BIT_ATTRIB_0_POINTER + attribIndex);
+    setDirtyAttribBit(attribIndex, DIRTY_ATTRIB_POINTER);
 }
 
 void VertexArray::setElementArrayBuffer(const Context *context, Buffer *buffer)
@@ -264,8 +274,15 @@ void VertexArray::syncState(const Context *context)
 {
     if (mDirtyBits.any())
     {
-        mVertexArray->syncState(context, mDirtyBits);
+        mVertexArray->syncState(context, mDirtyBits, mDirtyAttribBits, mDirtyBindingBits);
         mDirtyBits.reset();
+
+        // This is a bit of an implementation hack - but since we know the implementation
+        // details of the dirty bit class it should always have the same effect as iterating
+        // individual attribs. We could also look into schemes where iterating the dirty
+        // bit set also resets it as you pass through it.
+        memset(&mDirtyAttribBits, 0, sizeof(mDirtyAttribBits));
+        memset(&mDirtyBindingBits, 0, sizeof(mDirtyBindingBits));
     }
 }
 

src/libANGLE/VertexArray.h

@@ -153,40 +153,54 @@ class VertexArray final : public LabeledObject
         return mState.getEnabledAttributesMask();
     }
 
+    // Dirty bits for VertexArrays use a heirarchical design. At the top level, each attribute
+    // has a single dirty bit. Then an array of MAX_ATTRIBS dirty bits each has a dirty bit for
+    // enabled/pointer/format/binding. Bindings are handled similarly. Note that because the
+    // total number of dirty bits is 33, it will not be as fast on a 32-bit machine, which
+    // can't support the advanced 64-bit scanning intrinsics. We could consider packing the
+    // binding and attribute bits together if this becomes a problem.
     enum DirtyBitType
     {
         DIRTY_BIT_ELEMENT_ARRAY_BUFFER,
 
-        // Reserve bits for enabled flags
-        DIRTY_BIT_ATTRIB_0_ENABLED,
-        DIRTY_BIT_ATTRIB_MAX_ENABLED = DIRTY_BIT_ATTRIB_0_ENABLED + gl::MAX_VERTEX_ATTRIBS,
+        // Dirty bits for attributes.
+        DIRTY_BIT_ATTRIB_0,
+        DIRTY_BIT_ATTRIB_MAX = DIRTY_BIT_ATTRIB_0 + gl::MAX_VERTEX_ATTRIBS,
 
-        // Reserve bits for attrib pointers
-        DIRTY_BIT_ATTRIB_0_POINTER   = DIRTY_BIT_ATTRIB_MAX_ENABLED,
-        DIRTY_BIT_ATTRIB_MAX_POINTER = DIRTY_BIT_ATTRIB_0_POINTER + gl::MAX_VERTEX_ATTRIBS,
+        // Dirty bits for bindings.
+        DIRTY_BIT_BINDING_0   = DIRTY_BIT_ATTRIB_MAX,
+        DIRTY_BIT_BINDING_MAX = DIRTY_BIT_BINDING_0 + gl::MAX_VERTEX_ATTRIB_BINDINGS,
 
-        // Reserve bits for changes to VertexAttribFormat
-        DIRTY_BIT_ATTRIB_0_FORMAT   = DIRTY_BIT_ATTRIB_MAX_POINTER,
-        DIRTY_BIT_ATTRIB_MAX_FORMAT = DIRTY_BIT_ATTRIB_0_FORMAT + gl::MAX_VERTEX_ATTRIBS,
-
-        // Reserve bits for changes to VertexAttribBinding
-        DIRTY_BIT_ATTRIB_0_BINDING   = DIRTY_BIT_ATTRIB_MAX_FORMAT,
-        DIRTY_BIT_ATTRIB_MAX_BINDING = DIRTY_BIT_ATTRIB_0_BINDING + gl::MAX_VERTEX_ATTRIBS,
+        DIRTY_BIT_UNKNOWN = DIRTY_BIT_BINDING_MAX,
+        DIRTY_BIT_MAX     = DIRTY_BIT_UNKNOWN,
+    };
 
-        // Reserve bits for changes to BindVertexBuffer
-        DIRTY_BIT_BINDING_0_BUFFER   = DIRTY_BIT_ATTRIB_MAX_BINDING,
-        DIRTY_BIT_BINDING_MAX_BUFFER = DIRTY_BIT_BINDING_0_BUFFER + gl::MAX_VERTEX_ATTRIB_BINDINGS,
+    // We want to keep the number of dirty bits within 64 to keep iteration times fast.
+    static_assert(DIRTY_BIT_MAX <= 64, "Too many vertex array dirty bits.");
 
-        // Reserve bits for binding divisors
-        DIRTY_BIT_BINDING_0_DIVISOR = DIRTY_BIT_BINDING_MAX_BUFFER,
-        DIRTY_BIT_BINDING_MAX_DIVISOR =
-            DIRTY_BIT_BINDING_0_DIVISOR + gl::MAX_VERTEX_ATTRIB_BINDINGS,
+    enum DirtyAttribBitType
+    {
+        DIRTY_ATTRIB_ENABLED,
+        DIRTY_ATTRIB_POINTER,
+        DIRTY_ATTRIB_FORMAT,
+        DIRTY_ATTRIB_BINDING,
+        DIRTY_ATTRIB_UNKNOWN,
+        DIRTY_ATTRIB_MAX = DIRTY_ATTRIB_UNKNOWN,
+    };
 
-        DIRTY_BIT_UNKNOWN = DIRTY_BIT_BINDING_MAX_DIVISOR,
-        DIRTY_BIT_MAX     = DIRTY_BIT_UNKNOWN,
+    enum DirtyBindingBitType
+    {
+        DIRTY_BINDING_BUFFER,
+        DIRTY_BINDING_DIVISOR,
+        DIRTY_BINDING_UNKNOWN,
+        DIRTY_BINDING_MAX = DIRTY_BINDING_UNKNOWN,
     };
 
     using DirtyBits = angle::BitSet<DIRTY_BIT_MAX>;
+    using DirtyAttribBits       = angle::BitSet<DIRTY_ATTRIB_MAX>;
+    using DirtyBindingBits      = angle::BitSet<DIRTY_BINDING_MAX>;
+    using DirtyAttribBitsArray  = std::array<DirtyAttribBits, gl::MAX_VERTEX_ATTRIBS>;
+    using DirtyBindingBitsArray = std::array<DirtyBindingBits, gl::MAX_VERTEX_ATTRIB_BINDINGS>;
 
     static size_t GetVertexIndexFromDirtyBit(size_t dirtyBit);
 
@@ -201,10 +215,15 @@ class VertexArray final : public LabeledObject
   private:
     ~VertexArray() override;
 
+    void setDirtyAttribBit(size_t attribIndex, DirtyAttribBitType dirtyAttribBit);
+    void setDirtyBindingBit(size_t bindingIndex, DirtyBindingBitType dirtyBindingBit);
+
     GLuint mId;
 
     VertexArrayState mState;
     DirtyBits mDirtyBits;
+    DirtyAttribBitsArray mDirtyAttribBits;
+    DirtyBindingBitsArray mDirtyBindingBits;
 
     rx::VertexArrayImpl *mVertexArray;
 };

src/libANGLE/VertexArray_unittest.cpp

@@ -19,7 +19,7 @@ using namespace gl;
 TEST(VertexArrayTest, VerifyGetIndexFromDirtyBit)
 {
     VertexArray::DirtyBits dirtyBits;
-    constexpr size_t bits[] = {1, 4, 9, 16, 25, 36, 49, 64, 81, 92};
+    constexpr size_t bits[] = {1, 4, 9, 16, 25};
     constexpr GLint count   = sizeof(bits) / sizeof(size_t);
     for (GLint i = 0; i < count; i++)
     {
@@ -29,29 +29,13 @@ TEST(VertexArrayTest, VerifyGetIndexFromDirtyBit)
     for (size_t dirtyBit : dirtyBits)
     {
         const size_t index = VertexArray::GetVertexIndexFromDirtyBit(dirtyBit);
-        if (dirtyBit < VertexArray::DIRTY_BIT_ATTRIB_MAX_ENABLED)
+        if (dirtyBit < VertexArray::DIRTY_BIT_ATTRIB_MAX)
         {
-            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_ATTRIB_0_ENABLED, index);
+            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_ATTRIB_0, index);
         }
-        else if (dirtyBit < VertexArray::DIRTY_BIT_ATTRIB_MAX_POINTER)
+        else if (dirtyBit < VertexArray::DIRTY_BIT_BINDING_MAX)
         {
-            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_ATTRIB_0_POINTER, index);
-        }
-        else if (dirtyBit < VertexArray::DIRTY_BIT_ATTRIB_MAX_FORMAT)
-        {
-            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_ATTRIB_0_FORMAT, index);
-        }
-        else if (dirtyBit < VertexArray::DIRTY_BIT_ATTRIB_MAX_BINDING)
-        {
-            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_ATTRIB_0_BINDING, index);
-        }
-        else if (dirtyBit < VertexArray::DIRTY_BIT_BINDING_MAX_BUFFER)
-        {
-            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_BINDING_0_BUFFER, index);
-        }
-        else if (dirtyBit < VertexArray::DIRTY_BIT_BINDING_MAX_DIVISOR)
-        {
-            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_BINDING_0_DIVISOR, index);
+            EXPECT_EQ(dirtyBit - VertexArray::DIRTY_BIT_BINDING_0, index);
         }
         else
             ASSERT_TRUE(false);

src/libANGLE/renderer/VertexArrayImpl.h

@@ -21,7 +21,10 @@ class VertexArrayImpl : angle::NonCopyable
 {
   public:
     VertexArrayImpl(const gl::VertexArrayState &state) : mState(state) {}
-    virtual void syncState(const gl::Context *context, const gl::VertexArray::DirtyBits &dirtyBits)
+    virtual void syncState(const gl::Context *context,
+                           const gl::VertexArray::DirtyBits &dirtyBits,
+                           const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                           const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
     {
     }
 
@@ -32,6 +35,6 @@ class VertexArrayImpl : angle::NonCopyable
     const gl::VertexArrayState &mState;
 };
 
-}
+}  // namespace rx
 
 #endif // LIBANGLE_RENDERER_VERTEXARRAYIMPL_H_

src/libANGLE/renderer/d3d/d3d11/VertexArray11.cpp

@@ -57,7 +57,9 @@ void VertexArray11::destroy(const gl::Context *context)
 }
 
 void VertexArray11::syncState(const gl::Context *context,
-                              const gl::VertexArray::DirtyBits &dirtyBits)
+                              const gl::VertexArray::DirtyBits &dirtyBits,
+                              const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                              const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
 {
     ASSERT(dirtyBits.any());
 

src/libANGLE/renderer/d3d/d3d11/VertexArray11.h

@@ -27,7 +27,9 @@ class VertexArray11 : public angle::ObserverInterface, public VertexArrayImpl
     void destroy(const gl::Context *context) override;
 
     void syncState(const gl::Context *context,
-                   const gl::VertexArray::DirtyBits &dirtyBits) override;
+                   const gl::VertexArray::DirtyBits &dirtyBits,
+                   const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                   const gl::VertexArray::DirtyBindingBitsArray &bindingBits) override;
     // This will flush any pending attrib updates and then check the dynamic attribs mask.
     bool hasActiveDynamicAttrib(const gl::Context *context);
     gl::Error updateDirtyAndDynamicAttribs(const gl::Context *context,

src/libANGLE/renderer/d3d/d3d9/VertexArray9.h

@@ -24,7 +24,9 @@ class VertexArray9 : public VertexArrayImpl
     VertexArray9(const gl::VertexArrayState &data) : VertexArrayImpl(data) {}
 
     void syncState(const gl::Context *context,
-                   const gl::VertexArray::DirtyBits &dirtyBits) override;
+                   const gl::VertexArray::DirtyBits &dirtyBits,
+                   const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                   const gl::VertexArray::DirtyBindingBitsArray &bindingBits) override;
 
     ~VertexArray9() override {}
 
@@ -35,12 +37,14 @@ class VertexArray9 : public VertexArrayImpl
 };
 
 inline void VertexArray9::syncState(const gl::Context *context,
-                                    const gl::VertexArray::DirtyBits &dirtyBits)
+                                    const gl::VertexArray::DirtyBits &dirtyBits,
+                                    const gl::VertexArray::DirtyAttribBitsArray &attribBits,
+                                    const gl::VertexArray::DirtyBindingBitsArray &bindingBits)
 {
     ASSERT(dirtyBits.any());
     Renderer9 *renderer = GetImplAs<Context9>(context)->getRenderer();
     mCurrentStateSerial = renderer->generateSerial();
 }
-}
+}  // namespace rx
 
 #endif // LIBANGLE_RENDERER_D3D_D3D9_VERTEXARRAY9_H_