Ok - could you elaborate on the first "this is what one would expect". What difference does it make whether I use two threads or 20 threads with one connection when all operations are serialized? Shouldn't both cases have the same throughput?
On Friday, 21. September 2012 at 03:52, Keith Medcalf wrote: > > With two threads, using only one connection (87.8 s) is actually slower than > > using two connections (66.7 s). The performance of using only one connection > > drastically increased until a thread count somewhere between 10 and 20 where > > it settles at about 11 seconds. Using one connection per thread reduces the > > elapsed time only from 66 to 55 seconds. > > > > > This is what one would expect. > > > * The virtual machine has 2 CPU cores assigned. When using only one > > connection, only one core seems to be used. When using one connection per > > thread, both cores are used. > > > > > This is also to be expected. > > Because thread access to the sqlite engine is serialized by a mutex, the OS > ought to set thread affinity for all operations running through the same > mutex to the same CPU. If you repeated the test using two connections only, > and spreading your threads amongst connections, you ought to be able to get > about 5 or 6 seconds with 10 to 20 threads per connection. > > > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org (mailto:sqlite-users@sqlite.org) > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > > _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
