Re: Slow I/O on USB media

[Andrea Vai <andrea.vai@unipv.it>]

Il giorno sab 8 giu 2019 alle ore 09:43 Andrea Vai
<andrea.vai@unipv.it> ha scritto:
>
>[...]
>
> Hi,
>   there is also something else I don't understand.
> Every time I build a kernel, then after booting it "uname -a" shows
> something like
>
> Linux [...] 4.19.0-rc5+ #12 SMP Sat Jun 8 00:26:42 CEST 2019 x86_64
> x86_64 x86_64 GNU/Linux
>
> where the number after "#" increments by 1 from the previous build.
>
> Now I have the same number (#12) after a new build, is it normal?
> Furthermore, "ls -lrt /boot/v*" shows the last lines to be
>
> -rw-r--r--. 1 root root 8648656  8 giu 00.35 /boot/vmlinuz-4.19.0-rc5+.old
> -rw-r--r--. 1 root root 8648656  8 giu 09.08 /boot/vmlinuz-4.19.0-rc5+
>
> and "diff /boot/vmlinuz-4.19.0-rc5+.old /boot/vmlinuz-4.19.0-rc5+"
> shows they are identical. Why? I expected that each bisect would lead
> to a different kernel.
> Assuming that the opposite can happen, does it mean that when I say
> i.e. "git bisect bad", then build a new kernel and see that is
> identical to the previous one I can run "git bisect bad" without
> booting into the new one and even making the test?
>
> Another thing I don't understand is that I told 4.20.0 to be good, so
> I would expect that I don't need to test any older version, but as far
> as I know 4.19.0-rc5+ is older than 4.20.0, so why is it involved in
> the bisection?
>
> I had to "git bisect skip" one time (the kernel did not boot), but as
> far as I know I don't think this could be related to my doubts.
> [...]

Update:
  I have concluded the bisection, found that
"9cb5f4873b993497d462b9406f9a1d8a148e461b is the first bad commit",
reverted it, and the test still fails (btw, the final kernel file,
/boot/vmlinuz-4.19.0-rc5+, does not differ from the previous one).

So, all my doubts above are still there (and growing). What I am doing wrong?

Thank you,
Andrea