Bug 203757

Summary: Slow I/O on USB media
Product: Drivers Reporter: andrea.vai
Component: USBAssignee: Greg Kroah-Hartman (greg)
Status: NEW ---    
Severity: normal CC: andrea.vai
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 5.0.1 Subsystem:
Regression: No Bisected commit-id:

Description andrea.vai 2019-05-30 06:52:27 UTC 
I am experiencing slow I/O performance since kernel 5.0.1. File operations are roughly 10 times slower than they used to be using kernel up to 4.20. The problem is present when I use an USB pendrive, and does not happen when I copy a file from an internal SATA to another internal SATA hard disk.

You can see the discussion in the dar (backup software) mailing list [1], because I first noticed the problem using dar, but then discovered that also usual file operations such as “cp” suffer the same problem.

Steps to Reproduce:
Copy a file (e.g. roughly 1GB) from an internal SATA HD to an USB pendrive using "cp", using kernel 5.0.1+

Actual Results:
The file is copied in about 12 minutes

Expected Results:
The file is copied in about 1 minute (as it happens with kernel up to 4.20.13)

Running Fedora 29 on a Desktop PC.
Kernels found to be affected: e.g. 5.0.7, 5.0.9, 5.0.10, 5.0.13, 5.0.14, 5.0.17.

[1]:[https://sourceforge.net/p/dar/mailman/dar-support/thread/d490b5733731cbbb526d759c858a4b11a52fd179.camel%40unipv.it/#msg36660380](dar mailing list archive)
Comment 1 Greg Kroah-Hartman 2019-05-30 11:58:15 UTC 
On Thu, May 30, 2019 at 06:52:27AM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=203757
> 
>             Bug ID: 203757
>            Summary: Slow I/O on USB media
>            Product: Drivers
>            Version: 2.5
>     Kernel Version: 5.0.1

All USB bugs should be sent to the linux-usb@vger.kernel.org mailing
list, and not entered into bugzilla.  Please bring this issue up there,
if it is still a problem in the latest kernel release.