Re: Regression from 3.4.9 to 3.4.16 "stable" kernel

Mark Lord
2012-10-30T04:53:10Z

On 12-10-29 07:03 PM, Greg Kroah-Hartman wrote:
> On Mon, Oct 29, 2012 at 07:00:54PM -0400, Mark Lord wrote:
>> There's something else very wrong when going from 3.4.9 to 3.4.16.
>> I've done it on two machines here, one the AMD-450 server (64-bit),
>> and the other my main notebook (Core2duo 32-bit-PAE).
>>
>> Both systems feel much more sluggish than usual with 3.4.16 running.
>> Reverted them both back to earlier kernels (3.4.9, 3.4.4-PAE),
>> and the usual responsive feel has returned.
>>
>> Vague, I know, but something bad happened in there somewhere.
>
> That's too vague for me to do anything with, sorry. Bisection would be
> good if you can figure out how to measure this.

Well, I'd bet Donkeys to Daises that reverting the kernel/sched.c changes
will probably fix the responsiveness, but I haven't done that yet.
I've lost enough time already debugging the other issues.

This is more just an indication that perhaps -stable patches need better review
than they're getting. Take the setup.c breakage: as soon as I pointed it out,
a few people jumped in with knowledge that it was broken, and that patches
existed to fix it.

That kind of thing should be happening before a -stable release,
though I don't know how you would get the Right People to look
at this stuff then rather than after the fact. Maybe a topic
for a future kernel summit or something.

Best wishes.
-ml