On Wed, Oct 17, 2012 at 11:57 PM, Andrea Suisani <sickpig@xxxxxxxxxxxx> wrote: > On 10/17/2012 06:35 PM, Scott Marlowe wrote: >> >> On Wed, Oct 17, 2012 at 9:45 AM, Andrea Suisani <sickpig@xxxxxxxxxxxx> >> wrote: >>> >>> On 10/15/2012 05:34 PM, Scott Marlowe wrote: >>>> >>>> I'd recommend more synthetic benchmarks when trying to compare systems >>>> like this. bonnie++, >>> >>> >>> >>> you were right. bonnie++ (-f -n 0 -c 4) show that there's very little (if >>> any) >>> difference in terms of sequential input whether or not cache is enabled >>> on >>> the >>> RAID1 (SAS 15K, sdb). > > > Maybe there's a misunderstanding here.. :) Craig (James) is the one > the had started this thread. I've joined later suggesting a way to > disable HT without rebooting (using sysfs interface), trying to avoid > a trip to the data-center to Craig. > > At that point Claudio Freire wondering if disabling HT from sysfs > would have removed the performance penalty that Craig has experienced. > > So I decided to test this on a brand new box that I've just bought. > > When performing this test I've discovered by chance that > the raid controller (PERC H710) behave in an unexpected way, > cause the hw cache has almost no effect in terms of TPS in > a pgbench session. > >> I'm mainly wanting to know the difference between the two systems, so >> if you can run it on the old and new machine and compare that that's >> the real test. > > > This is something that Craig can do. Too late ... the new machine is in production. Craig > > [cut] > >>> I dunno why but I would have expected a higher delta (due to the 512MB >>> cache) >>> not a mere 10MB/s, but this is only based on my gut feeling. > >> >> >> Well the sequential throughput doesn't really rely on caching. It's >> the random writes that benefit from caching, and the other things >> (random reads and seq read/write) that indirectly benefit because the >> random writes are so much faster that they no longer get in the way. >> So mostly compare random access between the old and new machines and >> look for differences there. > > > make sense. > > I will focus on tests that measure random path access. > >>>> the memory stream test that Greg Smith was >>>> working on, and so on. >>> >>> >>> >>> this one https://github.com/gregs1104/stream-scaling, right? >> >> >> Yep. >> >>> I've executed the test with HT enabled, HT disabled from the BIOS >>> and HT disable using sys interface. Attached 3 graphs and related >>> text files >> >> >> Well it's pretty meh. > > > :/ > > do you think that Xeon Xeon 5620 perform poorly ? > >> I'd like to see the older machine compared to >> the newer one here tho. > > > also this one is on Craig side. > >>> I'm trying... hard :) >> >> >> You're doing great. These problems take effort to sort out. > > > thanks > > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
