----- Original Message ----- From: "Luis Alberto Amigo Navarro" <[EMAIL PROTECTED]> To: "Neil Conway" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Wednesday, November 06, 2002 5:02 PM Subject: Re: [HACKERS] a tiny question
> A small patch for low performance on NUMA arquitectures could be the chance > of using more than one shared region. > Several months away there was a brief talk about low performance on IRIX, it > was not real, it's low performance on Origin servers, they use ccNUMA > architecture, so using a single shared segment allocated by only one > proccess doesn't give IRIX planner a chance for attempting to optimize > memory accesses, even thought page migration is almost impossible with DB > memory accesses. > With this scenario, IRIX uses a first-touch algorith for memory placement > (all the memory is allocated on the node Postgres starts running). Due to > high latency between local and remote memory accesses, if there is data > modification, remote proccesors cache hit rate goes down, all of this makes > that all the basis of high scalability on this systems(big cache, memory > distribution, increasing bandwith and page migration) ar thrown to the > earth. > I suppose that making more than one shared segment it's not too difficult, > but with this u can do that a long time Postgres running on a NUMA system > achieve a good performance scenario. > Is it so difficult? > Thanks and regards. > Luis Amigo > > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED]) > > ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly