Request for assistance with a bug
Apologies for this long message in advance :)
I'm an Ubuntu user who is having an ongoing problem with USB file
transfers. This issue also seems to be affecting a significant number
of other Ubuntu users, and I have also been reading reports of it
appearing in other distros. I've reported it to the Ubuntu devs,
however their investigations only went as far as testing for it on one
or two computers, not finding it, and labeling it as low priority
because it's a problem that "only some people get". Despite repeated
attempts, I haven't been able to get them interested in investigating
any further.
This is the issue: USB file transfers start off at full speed, the
rapidly slow down, to speeds as low as 2mb/s, irrespective of the USB
device, whether it's flash drive or a HDD. Many of the users that are
being affected are experiencing it to different degrees, some get half
the USB transfer speeds they are expecting, others get the full
slowdown. Additionally, it doesn't always happen. In my experience,
I've occasionally had a transfer speed at near the expected rate, but
that's been rare. This problem also seems to affect Samba and UFS file
transfers as well. I've got a DLink DNS-323 and I'm typically getting
2mb/s transfers over the network when copying files to it, which makes
backing up my 100GB home folder, somewhat of a pain :)
Furthermore, this problem affects the GUI's responsiveness if a slow
file transfer is allowed to continue running for a long time. What
happens is that performance of the GUI slows to almost the point of
being unusable, windows are being redrawn in slow motion and key presses
take seconds to be detected. At the same time, the CPU is barely
registering any activity. Cancelling the file transfer restores the
system's performance immediately.
Most of the time this problem only shows up when copying a significant
amount of data, somewhere over 100mb. Because it requires a lot of data
to appear, I believe it's actually affecting a lot more users than are
reporting it since it goes unnoticed while just copying a few text files
around.
I own two computers, a laptop and a desktop and both are affected, and
I'm not the only one in the Ubuntu forums who is reporting seeing this
on multiple computers. It seems to be randomly affecting all types of
hardware, Intel, AMD, ATI, nVidia, I've even seen one report of this on
the eeePC.
This is the Ubuntu bug report:
https://bugs.launchpad.net/ubuntu/+source/gvfs/+bug/197762
I recently happened upon a partial solution, that has at least enabled
me to stop booting a live CD to copy files. I added "pci=routeirq" to
my boot options and it restored about 80% of my USB file transfer speed
on both my computers, though I'm still only getting 10mb/s via Samba to
the DNS-323, at least it's sustained and it doesn't slow the GUI down,
so I can live with it. This solution has also worked to various
degrees for some of the other people that are affected, but there seems
to be a new thread starting every other day now relating to this
problem, so we (the affected users) need to find a permanent solution
because although this isn't a "critical" problem, the frustration factor
is huge.
Can anyone help me narrow down what is causing this problem, or at least
point me towards someone who is capable of investigating it? At a
guess, I'd say it's a kernel problem, but I really can't be sure. I
need to find a developer who can reproduce the issue, but I don't know
where to go, since it doesn't affect everyone, and it can be quite
subtle. It would also be good to know if any Debian users have hit this
problem. I've checked the Debian bug reports but I can't find any
mention of it, but I could just be using the wrong keywords or package name.
Thanks in advance for any assistance or advice!
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