Re: multithread in INFORMIX, how? -Reply
With respect I think the point might have been missed here. The literature on DSA and the commonly accepted wisdom has been that the overhead in turning on mutex locking when moving from one CPU to two could well chew up any of the benefit gained by the extra CPU. For this reason the recommendation has been to run on either one CPU with mutex locking turned off, or a minimum of three. In my own experience running our test systems on a dual CPU sparc with both CPUs configured for the Online instance seems to yeild superior performance to a single CPU being allocated. It could be that this commonly held wisdom has originated from Informix being initially too conservative in making their recommendations, or it could be that the excessive burden of mutex locking varies between platforms. rgds -- -- Peter Tashkoff <tashkop@kiwi.co.nz> NZ Kiwifruit Marketing Board Usual disclaimers apply. This posting may not be used by any party to vilify another. >>> Brian Hampson <brian@asl-labs.bc.ca> 4/September/1996 05:35pm >>> Mike Segel (mikey@segel.com) wrote: : Chao Y. Din wrote: : > Saeed Talebbeik wrote: : > > : > > I have heard repeatedly that on machines with two CPU's The performance : > We have completely different experience. One of the production system : > we developed had performance problem, and users complaint constantly. : > After upgrading from one CPU to two CPUs and making necessary changes in : > the onconfig file, they all were pleased with the performance : > improvement. We never heard about performance problem since then. It : > has been over a year now. : > : I have to aggree with Chao. : : Someone with no or little understanding of how SMP works, or : how to tune an engine started this rumor. Hold on..... Look at what he typed! He said performance was dismal on a ONE CPU machine. Of course it got MUCH better when he threw TWO CPUS together...He probably could have TUNED it miserably, and STILL have seen an improvement over the 1 cpu days. B. -- ------------------------------------------------------------------------ |Brian P. Hampson Internet: brian@asl-labs.bc.ca | |System Administrator, | |Analytical Service Labs Fidonet : Brian Hampson 1:153/733 | |Vancouver, BC | |+604-253-4188 | | Specialists in Environmental Chemistry | | | ------------------http://www.asl-labs.bc.ca/----------------------------