optimize batching

- removes redundant MI_BATCH_BUFFER_START when target is within same command
buffer
- this way we do not have jump in command buffer

Signed-off-by: Michal Mrozek <[email protected]>

Author: MichalMrozek

shared/source/command_stream/command_stream_receiver_hw_base.inl

@@ -702,7 +702,9 @@ inline bool CommandStreamReceiverHw<GfxFamily>::flushBatchedSubmissions() {
             if (DebugManager.flags.FlattenBatchBufferForAUBDump.get()) {
                 flatBatchBufferHelper->registerCommandChunk(primaryCmdBuffer.get()->batchBuffer, sizeof(MI_BATCH_BUFFER_START));
             }
+
             while (nextCommandBuffer && nextCommandBuffer->inspectionId == primaryCmdBuffer->inspectionId) {
+
                 //noop pipe control
                 if (currentPipeControlForNooping) {
                     if (DebugManager.flags.AddPatchInfoCommentsForAUBDump.get()) {
@@ -718,14 +720,24 @@ inline bool CommandStreamReceiverHw<GfxFamily>::flushBatchedSubmissions() {
                 flushStampUpdateHelper.insert(nextCommandBuffer->flushStamp->getStampReference());
                 auto nextCommandBufferAddress = nextCommandBuffer->batchBuffer.commandBufferAllocation->getGpuAddress();
                 auto offsetedCommandBuffer = (uint64_t)ptrOffset(nextCommandBufferAddress, nextCommandBuffer->batchBuffer.startOffset);
-                addBatchBufferStart((MI_BATCH_BUFFER_START *)currentBBendLocation, offsetedCommandBuffer, false);
+                auto cpuAddressForCommandBufferDestination = ptrOffset(nextCommandBuffer->batchBuffer.commandBufferAllocation->getUnderlyingBuffer(), nextCommandBuffer->batchBuffer.startOffset);
+                auto cpuAddressForCurrentCommandBufferEndingSection = alignUp(ptrOffset(currentBBendLocation, sizeof(MI_BATCH_BUFFER_START)), MemoryConstants::cacheLineSize);
+
+                //if we point to exact same command buffer, then batch buffer start is not needed at all
+                if (cpuAddressForCurrentCommandBufferEndingSection == cpuAddressForCommandBufferDestination) {
+                    memset(currentBBendLocation, 0u, ptrDiff(cpuAddressForCurrentCommandBufferEndingSection, currentBBendLocation));
+                } else {
+                    addBatchBufferStart((MI_BATCH_BUFFER_START *)currentBBendLocation, offsetedCommandBuffer, false);
+                }
+
                 if (DebugManager.flags.FlattenBatchBufferForAUBDump.get()) {
                     flatBatchBufferHelper->registerCommandChunk(nextCommandBuffer->batchBuffer, sizeof(MI_BATCH_BUFFER_START));
                 }
 
                 currentBBendLocation = nextCommandBuffer->batchBufferEndLocation;
                 lastTaskCount = nextCommandBuffer->taskCount;
                 nextCommandBuffer = nextCommandBuffer->next;
+
                 commandBufferList.removeFrontOne();
             }
             surfacesForSubmit.reserve(resourcePackage.size() + 1);