This one is for those of you compiling a custom kernel or staying on 10.04 LTS because of this issue on database servers in the 3.x kernels: https://lkml.org/lkml/2012/10/9/210
Ubuntu has released linux-image-3.11.0-13-generic for 12.04 in which that fix is included. It's actually been included since 3.9rc2, but Ubuntu skipped straight to 3.11.
And there was much rejoicing in the PostgreSQL community. At least from those of us who manage 12.04 LTS PostgreSQL servers!
For those of you who don't recall, here's a link to the big discussion thread:
One item of note on 3.11 is that the kernel.sched_migration_cost setting is now called kernel.sched_migration_cost_ns, so if you are setting that via sysctl, you will need to update your sysctl.conf or sysctl.d file after upgrade.
Now go upgrade your test servers and let us know how it performs! I've been burning in a new server for about 24 hours with pgbench and the 3.11.0-13-generic kernel and so far it's been stable and a good performer.