computer architecture by chris van horn. cpu basics “brains of the computer” fetch execute cycle...
Post on 29-Jan-2016
Embed Size (px)
Computer ArchitectureByChris Van Horn
CPU BasicsBrains of the ComputerFetch Execute CycleInstruction Branching
Control UnitManagerSends signals to other devices telling them what to do
System ClockSignals when it is ok to perform workCannot base CPU performance strictly by system clockComputer A: 12 cycles/instruction 1 GhzComputer B: 3 cycles/instruction 250 MHz
RegistersUser RegistersControl RegistersProgram CounterInstruction RegisterStatus FlagStack Pointer
ALUWhere the real work happensAdderMultiplierShifterEtc.
The BusProvides TransportationDataControl Signals3 Parts of the BusOther Bus TypesMaster/Slave relationship
InterruptsInterrupts processor when something needs its attentionThreading
PipeliningWorks like an assembly linePotential for large speed increaseLong vs. Short PipelinesDrawbacks
MemoryHierarchyRegistersCacheLevel 1Level 2Main MemoryMagnetic Disks
Multi Core FunWhy multi core?Why not just jack up the clock speed?
Intel Multi-core TechnologyHyper-ThreadingDual CoreCore Duo
Hyper-ThreadingDual core for the poorProcessor runs two threads at once
Intel Dual CoreTwo Complete Cores running at same frequencyIntel Pentium D2.8 3.4 GHzFSB 800 MHzCache (per core)900 Series 2MB800 Series 1MB
Intel Core DuoReplacement for Pentium MSpecs2MB L2 cache shared1.5 2.16 GHzFSB 667 MHz
AMD Dual Core TechnologyDesign Started EarlyDirect Connect ArchitectureOperton DualAthlon Dual-Core X2
OpteronSpecs1.8 2.4 GHzL1 cache 64 KB per coreL2 cache 1 MB per coreFSB 1GHz
Athlon Dual-Core X2Specs2.0 2.4 GHzL1 Cache128 KB instruction128 KB dataL2 Cache1-2MB per core1 GHz FSB
Dual-Core DuelAMD challenges Intel to a Duel (Opteron Vs. Xeon)Intel RefusesTests Run by SPEC (Standards Standard Performance Evaluation Corporation )
Test ResultsAMD declared itself the winnerLack of ResultsReporting may be skewed
CNET X2 vs. Pentium DCNET independent testAMD won every round of testsWhy?
Tests RunEveryday ComputingOffice Productivity (SysMark Scores)Internet Content Creation (SysMark Scores)GamingHalflife 2(fps)MultitaskingEncoding Video while Virus Scanner running (time to complete both)Photo EditingPhotoshop (resizing large photos)MP3 EncodingiTunes (time to encode album)Video EncodingSorenson Squeeze 4 (time to encode video)
Price Vs. Performance
Can do more stuff at onceLeads to more responsive computerMore than one thread run at a timeIn general able to do more stuff in the same amount of time
2. Thread level parallelism3. Intels way to accomplish more instructions per clock cycle4. One processor presented as two virtual processors can execute two thread simultaniously5. Does not increase speed as well as two processors but still gives a decent speed increasePretty much just sophisticated pipeliningShare interface to outside world - Very BadWith hyper-threading have four virtual cores.Leads to cooler less power hungry processorsMobile chip2. Shared L2 Cache3. lead to better Cache utilization4. Processors can share the cache so processor 1 does not have to write an item to ram thatProcessor 2 needs which limits front side bus activity5. Better power management if one core is working the other can go to sleep to save power6. Can easily dump cache to RAM which allows more power savingsStarted designing in late 90smoved memory controller and I/O into the main processor Direct Connect Architecture nomore Front Side Buseliminates bottlenecks and latency while being very flexibleflexible in that they do not have to major motherboard design work
Duel10.Tried to follow their own roadmap to get to the duel9.Decided to take the "front-side bus" to the duel; got stuck in a bottleneck8.The "Intel Inside" stickers they used to package the cores together keep melting7.Too busy rearranging the deck chairs on the Itanic6."Hey, we don't expect anyone to actually buy these things!5.Didn't want to compete when they realized that the duel would involve actual "rules" of fair competition4.They couldn't get a permit from the fire department to emit thatmuch heat3.No systems available yet --protective clothing used by manufacturers only safe for up to 149 watts 2. Dell told them they weren't allowed to participateAnd the number one reason Intel didnt accept the dual-core duel:1. Moore's Law has been replaced by "Paul's Paradox": the number of canceled products per year at Intel will double every year after the introduction of the AMD Opteronprocessor.
Values extracted from tests run