Re: Server recommendations
От | Ron Johnson |
---|---|
Тема | Re: Server recommendations |
Дата | |
Msg-id | 1065448648.17599.109.camel@haggis обсуждение исходный текст |
Ответ на | Re: Server recommendations (Shridhar Daithankar <shridhar_daithankar@persistent.co.in>) |
Список | pgsql-general |
On Mon, 2003-10-06 at 08:32, Shridhar Daithankar wrote: > Ron Johnson wrote: > > On Mon, 2003-10-06 at 01:43, Shridhar Daithankar wrote: > > >>The best performance is by running 32 bit applications on 64 bit kernel/hardware > >>, according to a migration guide by HP. The reasoning is using space optimally > > Does HP have any AMD64 servers? > > No. But while migrating from PA1.1 to PA2.0, they have had that pain..:-) And I > just went thr. opteron optimization guide from a link you provided. Basically > same stuff HP was pitching. > > And I also configured a system on laclinux.com, just for curiosity. 2x > 1.8GHz/4GB/36GBx2 10K RPM SCSI/Adaptec 29320 for $4800/- is damn cheap a system. > HP does not even start below $5K for 64 bit systems. > > >>Imagine, if every long in pg is 8byte that would be waste most of the times. > >>However given a native 8 byte integer/float is available, there is no reason to > >>use a 8 byte data type unless required. > >>From what I've read, longs are still 32-bit; it's only pointers > > that have upped to 64-bit. > > I thought under 64 bits short==2 bytes, int==4 bytes and long==8 bytes. i.e. > this is another architecture/word length where int != long in size. Sounds like we are saying the same thing. > >>Its about exploiting wide and fast bus of a 64bit machine in a most optimal > >>fashion. I think except for kernel and glibc, nothing else requires 64 bit in > >>general unless application insists on doing it's own caching. > > In PG's case, if the app uses BIGINT a lot, then 64-bit PG should > > be more efficient. > > Possibly. Source code availability has a great advantage here. Compile the way > you want. > > But still, as long as PG in itself does not use 8 byte data types exclusively, I > would like it to be a 32 bit app. A bigint is 8 byte on a 64 bit machine, > whether or not the app. is 32 bit. > > > Besides, in 64-bit mode, the compilers get to use 2x as many GP > > registers, which should increase performance. > > Well, if a 32 bit app. is optimised for opteron, compiler will use those > registers anyway..:-) At least on HP, such trick can be done. IMO thats very > handy.. Don't think it works that way in AMD64. The way I've read it, you only get "32-bit apps" when you compile with the 32-bit compiler switches, and thus it doesn't use the extra GPRs. -- ----------------------------------------------------------------- Ron Johnson, Jr. ron.l.johnson@cox.net Jefferson, LA USA "Fair is where you take your cows to be judged." Unknown
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