rawhide ext4/virtio FS performance hit (10x slower) ?

[Josh Boyer]

On Mon, May 7, 2012 at 8:43 AM, Jim Meyering <jim at meyering.net> wrote:
> Today I noticed that some tests from coreutils' test suite
> were taking far longer than they used to on rawhide.
> For example, run this command in an empty directory:
>
>  seq 200000|env time xargs touch
>
> it takes < 5s on F17 3.3.4-1.fc17.x86_64 ext4/sdb8/SSD, yet
> it takes 47s on rawhide 3.4.0-0.rc5.git5.1.fc18.x86_64 ext4/vda1/SSD
>
> 10x performance hit... ouch.
>
> Does anyone know why?

Rawhide has all the kernel debug options turned on.  It isn't
worthwhile doing a comparison when those are enabled.  You could try
again with the first -rc6 build that shows up, as that will have the
options disabled.

josh