Comment # 19 on bug 1169774 from Jiri Slaby

It seems that I managed to reproduce with custom-built kernel, so I am starting
bisection.

It seems that the problem is I/O.
> Device             tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read    kB_wrtn    kB_dscd
> vda             436.66       167.78      3114.85         0.00     935805   17372932          0
> vda             270.82       822.20      9404.21         0.00     760877    8702840          0


The first is 5.6 = bad, the second is good = 5.5. 3 times slower writes, 5
times slower reads. But it could be due to accumulation of I/O buffers. Let's
see if I can bisect it at last as I failed 2 times already (bisection lead to a
merge commit or so...).