Re: Writing to USB3 memory stick with 4.4 is 52 times slower than Win7 inside virtualbox

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On Sat, 6 Feb 2016, Oliver Neukum wrote:

> > In theory, the copy command in Windows shouldn't need to wait either.  
> > But then you'd run into trouble if you unplugged the USB device without 
> > first clicking on the "Safely remove hardware" button -- which 
> > essentially does a sync.
> 
> Well, not fully. Linux knows two modes. Full caching and totally
> synchronous operations. It seems to me we could do better.
> Like starting the write as soon as dirty blocks appear and do an
> fsync upon close.

Even that wouldn't really do just what Marc would like.  It would be
nice to have a version of cp that would display a progress indicator,
and every (say) 5% would do fdatasync.  Plus, of course, fsync upon
close.

My point being that this doesn't require any changes to the kernel -- 
neither the filesystem layer nor the USB stack.  It requires changes 
to the cp program.  Or a new (maybe even graphical) version of cp.

Alan Stern

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