Re: 3.15.4 runs *significantly* slower than 3.15.3 on iMX233 CPU

From: Guenter Roeck
Date: Mon Jul 07 2014 - 15:14:40 EST


On Mon, Jul 07, 2014 at 08:21:38PM +0200, Manuel Reimer wrote:
> Hello,
>
> maybe someone can help me to find the reason for this problem:
>
> If I run my iMX233 development board with an 3.15.3 kernel, then the
> performance is much better as with an 3.15.4 kernel.
>
> I have the first significant "hanging" here:
>
> [ 7.910000] sd 0:0:0:0: [sda] Attached SCSI removable disk
> [ 10.810000] random: nonblocking pool is initialized
> [ 24.310000] systemd[1]: systemd 214 running in system mode. (+PAM
> -AUDIT -SELINUX -IMA -SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ
> +SECCOMP -APPARMOR)
>
> After booting up it takes several seconds between entering the
> username and the password while with version 3.15.3 the password
> prompt appears almost immediately after entering the username.
>

Are you sure this did not just happen when you booted the new kernel
for the first time ? I have seen similar behavior with some distributions.

If it happens all the time, ie at subsequent boots as wel, you'll probably
have to bisect the problem. I have not seen an obvious culprit.

Guenter
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