is sc + ilp = rc - duke university.ppt

Is SC + ILP = RC?Chris Gniady, BabakFalsafr, and . VijaykumarPresented By Jacob HarerIdea?Use large amounts of memory ILP to increase speed in SC?Relax all memory order speculatively in each core.?Appear to all other cores to be non speculativeImplementation?Need 1)Speculate on both loads and stores2)Large speculative state3)No additional overhead4)Well behaved programs ?Store all instructions in a Speculative History Que (SHiQ)?Roll back data if speculative data is accessed before mits Roll Back?On Invalidation of speculatively loaded or stored data. ?On read of speculatively stored data?On replacement due to a miss?Stored in Block Lookup Table (BLT)?Roll back by restoring from the SHiQ?No speculation until pletesExample Processor 1 speculative load to BlockProcessor 1 Does some other workProcessor 1 speculative Store to BlockProcessor 2 load to Block Get sharedGet ExclusiveRoll Back from SHiQ, Send old non specula