Re: High CPU usage / load average after upgrading to Ubuntu 12.04

> From: Josh Berkus <josh(at)agliodbs(dot)com>
>To: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
>Cc: pgsql-performance(at)postgresql(dot)org
>Sent: Thursday, 21 February 2013, 3:14
>Subject: Re: [PERFORM] High CPU usage / load average after upgrading to Ubuntu 12.04
>
>
>> Sounds to me like your IO system is stalling on fsyncs or something
>> like that.  On machines with plenty of IO cranking up completion
>> target usuall smooths things out.
>
>It certainly seems like it does.  However, I can't demonstrate the issue
>using any simpler tool than pgbench ... even running four test_fsyncs in
>parallel didn't show any issues, nor do standard FS testing tools.
>

I've missed a load of this thread and just scanned through what I can see, so apologies if I'm repeating anything.

If the suspicion is the IO system and you've tuned everything you can think of; is there anything interesting in meminfo/iostat/vmstat before/during the stalls? If so can you cause anything similar via bonnie++ with the "-b" option?