Re: 2 or 4 cpu's running Informix OnLine 7.xx

In article <319139FE.200C@eds.com>, Greg Moye <msmcl301.gmoye01@eds.com> wrote: >Scott Ratliff wrote: >> >> dkabrbwj@e-mail.com wrote: >>snip..... >> No, that is not true. What is true is that the engine will run slower >> on a two processor machine if you set MULTIPROCESSOR to 1 (true) and >> SINGLE_CPU_VP to 0 (false) than if you had set MULTIPROCESSOR to 0 (false) >> and SINGLE_CPU_VP to 1 (true). IOW, it is slower on a two processor >> machine to configure the engine for multiprocessing than it is to just >> tell the engine you only have one. >> >> Scott Ratliff >> Systems Engineer >> CARS Information Systems Corp. >> scottr@carsinfo.com > >This concept has been bothering me for some time, so I'll wander out on a limb against >the common wisdom and say "I haven't seen it" (at least on our 2 way Sparc 1000E). > >What I see is that 1 CPU VP corresponds to 1 Unix process under Solaris 2.4. If I only >have one CPU VP, only one CPU runs it, the other one sits there doing nothing. When I >add the second VP, both physical processors will get busy and throughput improves. > >To say that adding the second VP (to use the second processor) introduces so much >locking/coordination overhead that it's better to just let one physical CPU sit idle >seems absurd to me and would constitute a sorry implementation on Informix's part. Yes I >know their manuals say this too. It still just doesn't add up for me. > >Is it possible that the behavior I see is related to Solaris (since I haven't seen other >Unixes in a similar config)??? > >-- >Greg Moye >Electronic Data Systems Corp. - Plano TX In a two-cpu situation, you want that second (apparently idle) CPU to be running your users' 4GL apps, which hopefully will be talking to the Online engine via shared memory attachment. :-) If your machine which is to be running the Online engine is to be *exclusively* a database server and run absolutely no other software except for the O/S, then you need to stick with just a very fast single CPU box, or go directly to at least four CPU's.... and then when you've got such a big installation that justifies a 4+ CPU SMP unix box, you'll be running out of network bandwidth. :-) :-) :-) (smileys, lots of smileys) -- ========================================================================= = Neal Howard neal@metronet.com '91 XLH-1200 DoD #686 '96 Glastron SL175= = "Fuzzy Wuzzy was a bear, Fuzzy Wuzzy had no hair. If Fuzzy Wuzzy = = had no hair, then Fuzzy Wuzzy wasn't Fuzzy, wuz he ?!!!" = = http://www.flash.net/~neal <-------My home page. = =========================================================================