Path: utzoo!mnetor!uunet!husc6!rutgers!rochester!PT.CS.CMU.EDU!K.GP.CS.CMU.EDU!lindsay From: lindsay@K.GP.CS.CMU.EDU (Donald Lindsay) Newsgroups: comp.arch Subject: Re: Single tasking the wave of the future? Message-ID: <511@PT.CS.CMU.EDU> Date: 14 Dec 87 17:35:33 GMT References: <201@PT.CS.CMU.EDU> <388@sdcjove.CAM.UNISYS.COM> <988@edge.UUCP> <1227@sugar.UUCP> <151@sdeggo.UUCP> <1423@cuuxb.ATT.COM> <439@xyzzy.UUCP> <440@xyzzy.UUCP> <36083@sun.uucp> <18@amelia.nas.nasa.gov> <2341@encore.UUCP> Sender: netnews@PT.CS.CMU.EDU Organization: Carnegie-Mellon University, CS/RI Lines: 17 Multitasking gives flexibility, which is considered virtuous. Interestingly, there are cases when you get a performance win by simulating a multiprocessor on a uniprocessor. For example, suppose you are searching a big tree of choices while solving a Travelling Salesman type problem. This has the nice property that there is variance in the individual compute times. So, if you have a (simulated) multiprocessor, some of the computations finish earlier than their peers. This gives the overall search new data (about lower bounds) which may allow you to kill some of the computations that haven't finished yet. This can save work, not only directly, but also by preventing the killed searches from generating offspring. -- Don lindsay@k.gp.cs.cmu.edu CMU Computer Science