Well, as you guys know I've been tinkering with sun-vs-linux postgres for a while trying to come up with reasons for the HUGE performance differences. We've all had our anecdotal thoughts (fork sucks, ipc sucks, ufs sucks, etc) and I've had a breakthrough.
Knowing that GCC only produces good code on x86 (and powerpc with apple's mods, but it is doubtful that is as good as ibm's power compiler) I decided to try out Sunsoft CC. I'd heard from more than one person/place that gcc makes abysmal sparc code. Given that the performance profiles for both the linux and sun boxes showed the same functions taking up most of the time I thought I'd see what a difference sunsoft could give me. So - hardware - Sun E450 4x400mhz ultrasparc IIi, 4GB ram, scsi soemthing disk. (not raid) solaris 2.6 Linux - 2xP3 500mhz, 2GB, scsi disk of some flavor (not raid) linux 2.2.17 (old I know!) So here's the results using my load tester (single connection per beater, repeats the query 1000 times with different input each time (we'll get ~20k rows back), the query is a common query around here. I discounted the first run of the test as caches populated. Linux - 1x - 35 seconds, 20x - 180 seconds Sun - gcc - 1x 60 seconds 20x 245 seconds Sun - sunsoft defaults - 1x 52 seonds 20x [similar to gcc most likely] Sun - sunsoft -fast - 1x 28 seconds 20x 164 seconds As you math guru's can probably deduce - that is a rather large improvement. And by rather large I mean hugely significant. With results like this, I think it warrants mentioning in the FAQ_Solaris, and probably the performance guide. Connecting will always be a bit slower. But I think most people realize that connecting to a db is not cheap. I think update/etc will cause more locking, but I think IO will become the bottle neck much sooner than lock/unlock will. (This is mostly anecdotal given how fast solaris can lock/unlock a semaphore and how much IO I know I have) Oh yes, with was with 7.3.4 and sunsoft cc Sun WorkShop 6 update 1 C 5.2 2000/09/11 (which is old, perhaps newer ones make even better code?) I'm not sure of PG's policy of non-gcc things in configure, but perhaps if we detect sunsoft we toss in the -fast flag and maybe make it the preferred one on sun? [btw, it compiled with no changes but it did spew out tons of warnings] comments? -- Jeff Trout <[EMAIL PROTECTED]> http://www.jefftrout.com/ http://www.stuarthamm.net/ ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
