Re: Regression: kernels since 2.6.26 are unusably slow

[Frans Pop <elendil@planet.nl>]

Adding maintainers involved with the commit in CC.

Aneurin Price wrote:
> Hi,
> Every kernel since 2.6.26 has been unusably slow for me - to the extent
> that I initially thought they were hanging on boot. Exactly how bad it is
> seems to vary, but it could take several minutes to boot, and then
> another minute or two to log in (with bash pegging the CPU as it loads).
> Everything seems to need vastly more CPU time than usual - it feels a
> little like I'm using a 486.
> 
> I've bisected the problem down to commit
> 42651f15824d003e8357693ab72c4dbb3e280836 (x86: fix trimming e820 with
> MTRR holes). Having basically no idea what that means, I thought I'd try
> building a kernel with MTRRs disabled, to see if that would make any
> difference, but no joy.
> 
> Can anyone give me some idea of where to go next, or let me know what
> further information I should provide?

Let's start with some basic info. Can you please send your kernel config 
and the output of 'dmesg' after a boot with a "slow" kernel?

Also, what distribution do you use (and what is its release/version)?

Cheers,
FJP