Comment 0 for bug 1290337

Symptoms are that as time goes by I/O gets slower and slower (primarily if not even only writes rather than reads).
It can be temporarily cured via /sbin/sysctl -w vm.drop_caches=2 and/or /sbin/sysctl -w vm.drop_caches=3 but the problem will re-appear again sooner rather than later.
The problem seems also somewhat proportional on how much RAM is allocated. It does not seem to appear with less than 8GB (i.e., i saw it first when switching to a 16GB laptop/ThinkPad w530) and is considerably worse when allowing all memory compared to, e.g., by using only ~14GB using the mem=14000M boot option.
The issue shows up at least since 12.10

This is almost certainly the same bug as https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1107150 but as that bug is now strangely closed and i got told to open a new one, here we go ...

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-18-generic 3.11.0-18.32
ProcVersionSignature: Ubuntu 3.11.0-18.32-generic 3.11.10.4
Uname: Linux 3.11.0-18-generic i686
NonfreeKernelModules: nvidia wl
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: msteiner 4131 F.... pulseaudio
 /dev/snd/controlC0: msteiner 4131 F.... pulseaudio
 /dev/snd/pcmC0D0p: msteiner 4131 F...m pulseaudio
 /dev/snd/seq: timidity 3237 F.... timidity
CRDA:
 country IN:
  (2402 - 2482 @ 40), (N/A, 20)
  (5170 - 5250 @ 40), (N/A, 20)
  (5250 - 5330 @ 40), (N/A, 20), DFS
  (5735 - 5835 @ 40), (N/A, 20)
Date: Mon Mar 10 17:47:12 2014
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=4a17fffe-b487-4abf-9df8-1846a925cf4b
MachineType: LENOVO 2449A35
MarkForUpload: True
ProcFB: 0 VESA VGA
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.11.0-18-generic root=/dev/mapper/babbage2-root ro acpi_osi=Linux mem=14000M nox2apic rcutree.rcu_idle_gp_delay=1
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-18-generic N/A
 linux-backports-modules-3.11.0-18-generic N/A
 linux-firmware 1.116.2
SourcePackage: linux
UpgradeStatus: Upgraded to saucy on 2013-10-25 (135 days ago)
dmi.bios.date: 05/24/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: G5ET93WW (2.53 )
dmi.board.asset.tag: Not Available
dmi.board.name: 2449A35
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG5ET93WW(2.53):bd05/24/2013:svnLENOVO:pn2449A35:pvrThinkPadW530:rvnLENOVO:rn2449A35:rvrNotDefined:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2449A35
dmi.product.version: ThinkPad W530
dmi.sys.vendor: LENOVO