As you see InnoDB-plugin is doing much better here, it allows to utilize multiple IO threads,
which as we saw ( http://www.mysqlperformanceblog.com/2010/01/11/fusionio-320gb-mlc-benchmarks/ ) is necessary to get most throughput from FusionIO.
Also you may see from graph some waves for InnoDB-plugin. Here we observe innodb_adaptive_flushing in action (which is ON by default), and I think innodb_adaptive_flushing in InnoDB-plugin is not quite balanced, it may do overaggressive flushing, when it is not necessary.
But looking on CPU stats (see graph later), I guess InnoDB-plugin spends most time in buffer_pool mutex, contention here is not fully resolved yet in InnoDB-plugin.
Now, let#8217;s take XtraDB. In additional to multiple IO threads, we have patch to decrease contention on buffer_pool mutex, plus separate purge thread. Also we use different adaptive_checkpoint algorithm.
The results are:

So I guess buffer_pool improvements play here for XtraDB, and looking on summary result:

InnoDB 9439.316 NOTPM
InnoDB-plugin-1.0.6 15299.333 NOTPM
XtraDB-1.0.6-9 26160.551 NOTPM

InnoDB-plugin is 1.6x times better InnoDB, and XtraDB is 1.7x times better InnoDB-plugin.
Now on CPU usage and disk utilization.
Disk throughput:

CPU (user) usage:

Even with improvements, XtraDB performs less 150MB/s in disk writes (from benchmarks we
saw FusionIO can do much more) and with 45-50% of idle CPU.
I assume we still see significant contentions inside XtraDB, and there big room for improvements. As for InnoDB-plugin, I#8217;d wish InnoDB team makes some actions on buffer_pool mutex problem.
Finally I wanted to check what if we put innodb transactional logs and system tablespace on FusionIO also, there is graph for that:

It is not so bad, with final result 23038.283 NOTPM, it is only about 12% worse than with logs on separate partition.
And to make reference point, I run the same but with all files on RAID10 with regular disks,
the graph is there:

with final result: 2873.783 NOTPM ( about 88% worse than all files on FusionIO)
To summarize

MySQL InnoDB/InnoDB-plugin/XtraDB is not fully able to utilize throughput of FusionIO. XtraDB is doing better job with internal contention, but much more can be done.
Still you can have very impressive performance improvement in IO-intensive or IO-bound workloads. You may want to use InnoDB-plugin or XtraDB to get better results.

Putting logs on separate partition may be good idea, but only if you have possibility to do that. Making special setup for that may be not worth improvements