From 2966d9c691fd0cd51d83204cac6b3194b9dcb878 Mon Sep 17 00:00:00 2001
From: Tim Rowley <timothy.o.rowley@intel.com>
Date: Tue, 4 Oct 2016 12:59:30 -0500
Subject: [PATCH] swr: [rasterizer core] align Macrotile FIFO memory to SIMD
 size

Align and use streaming store instructions for BE fifo queues.
Provides slightly faster enqueue and doesn't pollute the caches.
Add appropriate memory fences to ensure streaming writes are
globally visible.

Signed-off-by: Tim Rowley <timothy.o.rowley@intel.com>
---
 .../drivers/swr/rasterizer/common/simdintrin.h      |  1 +
 src/gallium/drivers/swr/rasterizer/core/context.h   |  2 +-
 src/gallium/drivers/swr/rasterizer/core/fifo.hpp    | 21 ++++++++++++++++-----
 src/gallium/drivers/swr/rasterizer/core/threads.cpp |  8 +++++---
 4 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/gallium/drivers/swr/rasterizer/common/simdintrin.h b/src/gallium/drivers/swr/rasterizer/common/simdintrin.h
index 4a91e95..3ad37de 100644
--- a/src/gallium/drivers/swr/rasterizer/common/simdintrin.h
+++ b/src/gallium/drivers/swr/rasterizer/common/simdintrin.h
@@ -114,6 +114,7 @@ OSALIGNSIMD(union) simdvector
 #define _simd_round_ps _mm256_round_ps
 #define _simd_castpd_ps _mm256_castpd_ps
 #define _simd_broadcast_ps(a) _mm256_broadcast_ps((const __m128*)(a))
+#define _simd_stream_ps _mm256_stream_ps
 
 #define _simd_load_sd _mm256_load_sd
 #define _simd_movemask_pd _mm256_movemask_pd
diff --git a/src/gallium/drivers/swr/rasterizer/core/context.h b/src/gallium/drivers/swr/rasterizer/core/context.h
index dfcc1c0..7a817ef 100644
--- a/src/gallium/drivers/swr/rasterizer/core/context.h
+++ b/src/gallium/drivers/swr/rasterizer/core/context.h
@@ -161,7 +161,7 @@ enum WORK_TYPE
     SHUTDOWN,
 };
 
-struct BE_WORK
+OSALIGNSIMD(struct) BE_WORK
 {
     WORK_TYPE type;
     PFN_WORK_FUNC pfnWork;
diff --git a/src/gallium/drivers/swr/rasterizer/core/fifo.hpp b/src/gallium/drivers/swr/rasterizer/core/fifo.hpp
index ccf0b70..7e07e6a 100644
--- a/src/gallium/drivers/swr/rasterizer/core/fifo.hpp
+++ b/src/gallium/drivers/swr/rasterizer/core/fifo.hpp
@@ -55,13 +55,11 @@ struct QUEUE
         mHead = 0;
         mTail = 0;
         mBlocks.clear();
-        T* pNewBlock = (T*)arena.Alloc(sizeof(T)*mBlockSize);
+        T* pNewBlock = (T*)arena.AllocAligned(sizeof(T)*mBlockSize, KNOB_SIMD_WIDTH*4);
         mBlocks.push_back(pNewBlock);
         mCurBlock = pNewBlock;
         mCurBlockIdx = 0;
-
         mNumEntries = 0;
-        _ReadWriteBarrier();
         mLock = 0;
     }
 
@@ -106,7 +104,20 @@ struct QUEUE
     template <typename ArenaT>
     bool enqueue_try_nosync(ArenaT& arena, const T* entry)
     {
-        memcpy(&mCurBlock[mTail], entry, sizeof(T));
+        const float* pSrc = (const float*)entry;
+        float* pDst = (float*)&mCurBlock[mTail];
+
+        auto lambda = [&](int32_t i)
+        {
+            __m256 vSrc = _simd_load_ps(pSrc + i*KNOB_SIMD_WIDTH);
+            _simd_stream_ps(pDst + i*KNOB_SIMD_WIDTH, vSrc);
+        };
+            
+        const uint32_t numSimdLines = sizeof(T) / (KNOB_SIMD_WIDTH*4);
+        static_assert(numSimdLines * KNOB_SIMD_WIDTH * 4 == sizeof(T),
+            "FIFO element size should be multiple of SIMD width.");
+
+        UnrollerL<0, numSimdLines, 1>::step(lambda);
 
         mTail ++;
         if (mTail == mBlockSize)
@@ -117,7 +128,7 @@ struct QUEUE
             }
             else
             {
-                T* newBlock = (T*)arena.Alloc(sizeof(T)*mBlockSize);
+                T* newBlock = (T*)arena.AllocAligned(sizeof(T)*mBlockSize, KNOB_SIMD_WIDTH*4);
                 SWR_ASSERT(newBlock);
 
                 mBlocks.push_back(newBlock);
diff --git a/src/gallium/drivers/swr/rasterizer/core/threads.cpp b/src/gallium/drivers/swr/rasterizer/core/threads.cpp
index 28cd929..08a4d17 100644
--- a/src/gallium/drivers/swr/rasterizer/core/threads.cpp
+++ b/src/gallium/drivers/swr/rasterizer/core/threads.cpp
@@ -565,8 +565,6 @@ bool WorkOnFifoBE(
 /// @brief Called when FE work is complete for this DC.
 INLINE void CompleteDrawFE(SWR_CONTEXT* pContext, DRAW_CONTEXT* pDC)
 {
-    _ReadWriteBarrier();
-
     if (pContext->pfnUpdateStatsFE && GetApiState(pDC).enableStats)
     {
         pContext->pfnUpdateStatsFE(GetPrivateState(pDC), &pDC->dynState.statsFE);
@@ -584,8 +582,9 @@ INLINE void CompleteDrawFE(SWR_CONTEXT* pContext, DRAW_CONTEXT* pDC)
         }
     }
 
+    // Ensure all streaming writes are globally visible before marking this FE done
+    _mm_mfence();
     pDC->doneFE = true;
-
     InterlockedDecrement((volatile LONG*)&pContext->drawsOutstandingFE);
 }
 
@@ -673,6 +672,9 @@ void WorkOnCompute(
                 queue.dispatch(pDC, workerId, threadGroupId, pSpillFillBuffer);
                 queue.finishedWork();
             }
+
+            // Ensure all streaming writes are globally visible before moving onto the next draw
+            _mm_mfence();
         }
     }
 }
-- 
2.7.4