This used to be a problem with early Unity (v5/v6?) doing I/O bound operations in threads used for rendering. Which is obviously bad. Maybe we haven't fully solved that yet or regressed.
Also, the choice of filesystem formats used on the USB drive could be a factor. In Ubuntu/Gnome/Nautilus I think the formats NTFS and ExFAT for example are handled in userspace via GVFS [1]. So try some USB drives that are ext2/ext3/ext4/FAT32 to compare. [1] https://en.wikipedia.org/wiki/GVfs Either way, there's no excuse for this bug. If it was fast in 14.04 then it should be at least as fast in 16.04. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1581651 Title: Xenial desktop unusable under simple I/O through USB Status in linux package in Ubuntu: Incomplete Status in linux source package in Xenial: Incomplete Bug description: Hello! After installing Xenial [0] I experience the following: when I do I/O through USB (to/from simple pendrives, or an external HDD I have), the desktop becomes unusable, because it goes very very unresponsive. With unresponsive I mean: - all windows go greyed out (like when it's failing to answer in time, as if the process inside that window locked up) - firefox and thunderbird start to pop up the typical "the script is taking too much to finis, want to kill it/continue/etc" (in whatever tab I'll be, so it's not the JS scripts (for once!) - the mouse pointer goes jumpy, not really following my hand movement - I see in thee indicator-multiload widget that CPU time is "wasted" in "waiting i/o"; which I confirmed looking at "top". So, in short: even while understanding that CPU would wait a little for i/o and that the system will be under a little load by writing a pen-drive, I find current situation beyond a normal experience. How can I start to debug this? What I can try? Can I provide you more info? Thanks! Regards, [0] from scratch, in the computer where I always work; I previously had Trusty here ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-21-generic 4.4.0-21.37 ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6 Uname: Linux 4.4.0-21-generic x86_64 NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: facundo 2338 F.... pulseaudio /dev/snd/controlC3: facundo 2338 F.... pulseaudio /dev/snd/controlC2: facundo 2338 F.... pulseaudio /dev/snd/controlC0: facundo 2338 F.... pulseaudio CurrentDesktop: Unity Date: Fri May 13 16:13:12 2016 HibernationDevice: RESUME=UUID=5dabff2e-722b-4c99-8bf5-003643ad0d04 InstallationDate: Installed on 2016-04-01 (42 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Beta amd64 (20160323) MachineType: Gigabyte Technology Co., Ltd. GA-970A-D3 ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic root=UUID=6ba5d9f5-e21f-4e58-800d-89ec0b7d1e9b ro quiet splash RelatedPackageVersions: linux-restricted-modules-4.4.0-21-generic N/A linux-backports-modules-4.4.0-21-generic N/A linux-firmware 1.157 RfKill: SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/13/2011 dmi.bios.vendor: Award Software International, Inc. dmi.bios.version: F7 dmi.board.name: GA-970A-D3 dmi.board.vendor: Gigabyte Technology Co., Ltd. dmi.board.version: x.x dmi.chassis.type: 3 dmi.chassis.vendor: Gigabyte Technology Co., Ltd. dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF7:bd10/13/2011:svnGigabyteTechnologyCo.,Ltd.:pnGA-970A-D3:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-970A-D3:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr: dmi.product.name: GA-970A-D3 dmi.sys.vendor: Gigabyte Technology Co., Ltd. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1581651/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp