Re: Slow I/O on USB media

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jun 05, 2019 at 09:36:04AM +0200, Andrea Vai wrote:
> Hi,
> Il giorno mar, 04/06/2019 alle 07.43 +0200, Greg KH ha scritto:
> > On Mon, Jun 03, 2019 at 01:13:48PM +0200, Andrea Vai wrote:
> > > Il giorno gio, 30/05/2019 alle 06.25 -0700, Greg KH ha scritto:
> > > > [...]
> > > Hi,
> > > 
> > > > Any chance you can use 'git bisect' to find the offending
> > commit?
> > > Yes, I am doing it as I managed to build the kernel from source
> > 
> > Great!  What did you find?
> 
> # first bad commit: [534903d60376b4989b76ec445630aa10f2bc3043]
> drm/atomic: Use explicit old crtc state in
> drm_atomic_add_affected_planes()
> 
> By the way, as I am not expert, is there a way to double-check that I
> bisected correctly? (such as, e.g., test with the version before this
> one, and then with this commit applied?)

How exactly are you "testing" this?

I would recommend a script that does something like:
	mount the disk somewhere
	copy a big file to it
	unmount the disk

testing how long the whole process takes, especially the 'unmount' is
important.  Are you doing that?

Also, you should probably just boot into text mode for this, most
graphical DEs like to auto-mount disks these days.

thanks,

greg k-h