Hello,
doWritebacks will only populate the write queue, which would then be emptied when possible. Since you are evicting a multitude of blocks simultaneously, the queue will become full and the assertion will trigger. You will either have to implement a specialized version of doWritebacks() for your use-case, or simply assume that these writebacks are done atomically and bypass the write queue with a call to doWritebacksAtomic(). Still, the second solution would probably not be that simple, because you will likely run into the same multi-eviction issue described in the last messages of https://gem5-review.googlesource.com/c/public/gem5/+/18209 Regards, Daniel Em quinta-feira, 16 de abril de 2020 16:43:12 GMT+2, 周泰宇 <645505...@qq.com> escreveu: Hi,DanielThanks for you reply. I’ve try to perform doWritebacks(..) before access(..). But It still can’t work for me. Cache will be blocked because writeBuffer.isFull() and finally gem5 will report that freeList has no space. Error report:gem5.opt: build/X86/mem/cache/write_queue.cc:64: WriteQueueEntry* WriteQueue::allocate(Addr, unsigned int, PacketPtr, Tick, Counter): Assertion `!freeList.empty()' failed. My new code is below BaseCache::recvTimingReq(pkt){ if(trigger){ //some instr will trigger this code section wb_pkts.clear(); dirty_blk_count = my_memWriteback(wb_pkts);+ doWritebacks(wb_pkts, clockEdge(lat+forwardLatency)); } bool satisfied = false; { PacketList writebacks; satisfied = access(pkt, blk, lat, writebacks); ..... } int BaseCache::my_memWriteback(PacketList &wb_pkts) { int count = 0; tags->forEachBlk([this,&count,&wb_pkts](CacheBlk &blk) mutable{ if(blk.isDirty()){ if(blk.isValid()){ count++; } } my_writebackVisitor(blk,wb_pkts); }); //printf("NmemWriteback count:%d\n",count); return count; } BaseCache::my_writebackVisitor(CacheBlk &blk,PacketList &writebacks) { if (blk.isDirty()) { assert(blk.isValid()); RequestPtr request = std::make_shared( regenerateBlkAddr(&blk), blkSize, 0, Request::funcMasterId); request->taskId(blk.task_id); if (blk.isSecure()) { request->setFlags(Request::SECURE); } - //PacketPtr packet = new Packet(request, MemCmd::WriteReq); + PacketPtr packet = new Packet(request, MemCmd::WriteReq);//should only see writes or clean evicts in allocateWriteBuffer packet->allocate(); std::memcpy(packet->getPtr, blk.data, blkSize); // packet->dataStatic(blk.data); writebacks.push_back(packet); blk.status &= ~BlkDirty; } }
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