Re: [ADMIN] postgres smp
just to avoid confusion - some more things: * smp and up case compared here were done on the same machine (linux 2.4.1-XFS, smp kernel booted with or without "nosmp") * the used hardware is a 2 pII333 128mb ide disk * the numbers were generated using pgbench from postgres-7.1beta4 with -c 32 -s 20 -t 100 * the results are ranging from ~17tps (reiserfs/smp) ... ~20-23tps (xfs/smp-up) one idea i have so far is that the pgbench queries are that simple that the whole benchmark is heavily disk bound and the second cpu only results in locking overhead resulting in a bit lower numbers) may this be the reason for the missing improvement in the numbers in the smp case? again - a lot of thanks in advance t Thomas Graichen [EMAIL PROTECTED] wrote: i hope this list is somewhat the right one for this ... i did some small tests with postgresql-71.beta4 on various filesystems (ext2, reiserfs, xfs) on two machines: 1 single cpu and one 2 cpu smp and was a bit surprised to see the tps results of the smp case to be lower than the one of the up case (also the running times of the used pgbench said the same) ... i was thinking that the load should spread over the cpu's and thus expected better results for smp - is there anything to take care of for smp with postgresql? did i anything wrong here? a lot of thanks in advance t p.s.: btw. i in all cases see about 15% better results with the database running on an xfs filesystem compared to ext2 ... reiserfs is about the same as ext2 but some- times even worse ... just if anyone is interested ... -- [EMAIL PROTECTED] innominate AG the linux architects tel: +49-30-308806-13 fax: -77 http://www.innominate.com -- [EMAIL PROTECTED] innominate AG the linux architects tel: +49-30-308806-13 fax: -77 http://www.innominate.com
Re: [ADMIN] postgres smp
Thomas Graichen [EMAIL PROTECTED] writes: i hope this list is somewhat the right one for this ... i did some small tests with postgresql-71.beta4 on various filesystems (ext2, reiserfs, xfs) on two machines: 1 single cpu and one 2 cpu smp and was a bit surprised to see the tps results of the smp case to be lower than the one of the up case Hm, did you set commit_delay to zero? What are the other postmaster parameters (especially -B) ? regards, tom lane
Re: [ADMIN] postgres smp
Tom Lane [EMAIL PROTECTED] wrote: Thomas Graichen [EMAIL PROTECTED] writes: i hope this list is somewhat the right one for this ... i did some small tests with postgresql-71.beta4 on various filesystems (ext2, reiserfs, xfs) on two machines: 1 single cpu and one 2 cpu smp and was a bit surprised to see the tps results of the smp case to be lower than the one of the up case Hm, did you set commit_delay to zero? What are the other postmaster parameters (especially -B) ? i used 32 clients -N set to 128 and -B to 256 - commit_delay was set to 5 (default) - do you expect much better smp results with commit_delay=0? what exaclty does commit_delay=0 mean or where can i find docs about this (and some of the other new parameters)? again - a lot of thanks in advance t -- [EMAIL PROTECTED] innominate AG the linux architects tel: +49-30-308806-13 fax: -77 http://www.innominate.com
