Daniel, Good stuff. Can you try this with just "-O3" versus "-O2"? - Luke On 12/11/06 2:22 PM, "Daniel van Ham Colchete" <daniel.colchete@xxxxxxxxx> wrote: > Hi yall, > > I made some preliminary tests. > > Before the results, I would like to make some acknowledgments: > 1 - I didn't show any prove to any of the things I said until now. > 2 - It really is a waste of everyone's time to say one thing when I > can't prove it. > > But all I said, is the knowledge I have been acumulating over the past > few years working on a project where optimization is important. After > algorithmic optimizations, compiler options is the second on my list > and with my software they show measurable improvement. With the other > software I use, they seen to run faster, but I didn't measure it. > > TEST PROCEDURE > ================ > I ran this test at a Gentoo test machine I have here. It's a Pentium 4 > 3.0GHz (I don't know witch P4) with 1 GB of RAM memory. It only uses > SATA drives. I didn't changed my glibc (or any other lib) during the > test. I used GCC 3.4.6. > > I ran each test three times. So we can get an idea about average > values and standard deviation. > > Each time I ran the test with the following commands: > dropdb mydb > createdb mydb > pgbench -i -s 10 mydb 2> /dev/null > psql -c 'vacuum analyze' mydb > psql -c 'checkpoint' mydb > sync > pgbench -v -n -t 600 -c 5 mydb > > My postgresql.conf was the default one, except for: > fsync = <depends on the test> > shared_buffers = 10000 > work_mem = 10240 > > Every test results should begin the above, but I removed it because > it's always the same: > transaction type: TPC-B (sort of) > scaling factor: 10 > number of clients: 5 > number of transactions per client: 600 > number of transactions actually processed: 3000/3000 > > TESTS RESULTS > ============== > TEST 01: CFLAGS="-O2 -march=i686" fsync=false > > tps = 734.948620 (including connections establishing) > tps = 736.866642 (excluding connections establishing) > > tps = 713.225047 (including connections establishing) > tps = 715.039059 (excluding connections establishing) > > tps = 721.769259 (including connections establishing) > tps = 723.631065 (excluding connections establishing) > > > TEST 02: CFLAGS="-O2 -march=i686" fsync=true > > tps = 75.466058 (including connections establishing) > tps = 75.485675 (excluding connections establishing) > > tps = 75.115797 (including connections establishing) > tps = 75.135311 (excluding connections establishing) > > tps = 73.883113 (including connections establishing) > tps = 73.901997 (excluding connections establishing) > > > TEST 03: CFLAGS="-O2 -march=pentium4" fsync=false > > tps = 846.337784 (including connections establishing) > tps = 849.067017 (excluding connections establishing) > > tps = 829.476269 (including connections establishing) > tps = 832.008129 (excluding connections establishing) > > tps = 831.416457 (including connections establishing) > tps = 835.300001 (excluding connections establishing) > > > TEST 04 CFLAGS="-O2 -march=pentium4" fsync=true > > tps = 83.224016 (including connections establishing) > tps = 83.248157 (excluding connections establishing) > > tps = 80.811892 (including connections establishing) > tps = 80.834525 (excluding connections establishing) > > tps = 80.671406 (including connections establishing) > tps = 80.693975 (excluding connections establishing) > > > CONCLUSIONS > Everyone can get their own conclusion. Mine is: > > 1 - You have improvement when you compile your postgresql using > processor specific tecnologies. With the fsync the you have an > improvement of 9% at the tps rate. Without the fsync, the improvement > is of 15,6%. > > 2 - You can still improve your indexes, sqls and everythingelse, this > only adds another possible improvment. > > 3 - I can't prove this but I *think* that this is related to the fact > that GCC knows how to do the same thing better on each processor. > > 4 - I'm still using source-based distros. > > WHAT NOW > There are other things I wish to test: > 1 - What efect an optimized glibc has on PostgreSQL? > 2 - How much improvement can I get playing with my postgresql.conf. > 3 - What efect optimizations have with concurrency? > 4 - What if I used Intel C++ Compiler instead of GCC? > 5 - What if I use GCC 4.1.1 instead of GCC 3.4.6? > > I'm thinking about writing a script to make all the tests (more than 3 > times each), get the data and plot some graphs. > > I don't have the time right now to do it, maybe next week I'll have. > > I invite everyone to comment/sugest on the procedure or the results. > > Best regards, > Daniel Colchete > > ---------------------------(end of broadcast)--------------------------- > TIP 2: Don't 'kill -9' the postmaster >
