On Fri, Feb 18, 2011 at 1:00 PM, Saman Barghi <[email protected]> wrote:
> It would be great if you had the SMP results as well. Anyway, I think you > would love this: > http://www.cs.uwaterloo.ca/~sbarghi/bench/transactions1.jpg > (keep in mind that this is a quad core xenon with 2 GB of RAM, and FreeBSD > is in SMP mode) > Could you try -master? There has been fairly substantial work since the 2.8 release; all of the tokens in 2.8 are still taking the MP lock as a precaution. That is no longer the case in master. The process token has been broken up fairly dramatically in master as well, so I expect to see different results. Can you give us a bit more information about the h/w and configuration? In Kris Kennaway's tests, he was seeing FreeBSD 7 sustain 8 times the number of transactions you're reporting for 8.1, and that was for hardware that is three or four years old at this point. Also, last I tried sysbench/OLTP with MySQL on dfly, I saw MySQL making many 256K allocations, which fall back to mmap() in our system. mmap() acquires the VM token, so I expected to see a much more dramatic falloff than you saw. I guess I wasn't clear earlier, the results on my graph were SMP; the UP lines were not present; the results were from very early in the 2.8 cycle, but I don't have the exact rev handy. > As I said before; I kept the environment the the same as what has been > mentioned here: http://people.freebsd.org/~kris/scaling/dfly.html . I even > used the same version of MySQL (5.0) although MySQL 5.5 shows better > scaling behaviour.( > http://mikaelronstrom.blogspot.com/2010/04/mysql-554-m3-scales-to-32-cores.html). > IMHO if "The multiprocessor work that has been ongoing in DragonFly is > really starting to bear fruit", the fruits are indeed juicy and sweet. It > would be lovely to see the results on a machine with more cores though. > > Btw, is there any changelog that shows what has been changed about tokens > !? > > Yes -- http://gitweb.dragonflybsd.org/dragonfly.git/commit/2a4189307741dbcfbe11b31d6cc51a4fb39a8cde was the commit that reworked the token contention path.This was not in 2.8, but is in master. Matt has seen improvements from in on a 48-core system he runs; I don't know that we've seen great things from it on smaller systems http://gitweb.dragonflybsd.org/dragonfly.git/commit/3b998fa96afe52828957ea4f65d15320eb0fe240 was the other one in particular I was referencing; that one produced a fairly noticeable bump in apache performance, among other things... -- vs
