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). 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. > I've run 2 bonnie++ test with both cache enabled and disabled and what I get > (see attachments for more details) it's a 400MB/s sequential input (cache) > vs > 390MBs (nocache). > > 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. >> 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. I'd like to see the older machine compared to the newer one here tho. > I'm trying... hard :) You're doing great. These problems take effort to sort out. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
