What's the value of `vm.dirty_writeback_centisecs` ?, ie.
$ sysctl vm.dirty_writeback_centisecs

try setting it to 0 to disable it, ie.
`$ sudo sysctl -w vm.dirty_writeback_centisecs=0`

I found that this helps my network transfer not stall/stop at all(for a
few seconds when that is =1000 for example) while some kinda of non-
async `sync`(command)-like flushing is going on periodically while
transferring GiB of data files from sftp to SSD!(via Midnight Commander,
on a link limited to 10MiB per second)

vm.dirty_writeback_centisecs is how often the pdflush/flush/kdmflush
processes wake up and check to see if work needs to be done.


Coupled with the above I've been using another value:
`vm.dirty_expire_centisecs=1000`
for both cases (when stall and not stall), so this one remained fixed to =1000.

vm.dirty_expire_centisecs is how long something can be in cache before
it needs to be written. In this case it's 1 seconds. When the
pdflush/flush/kdmflush processes kick in they will check to see how old
a dirty page is, and if it's older than this value it'll be written
asynchronously to disk. Since holding a dirty page in memory is unsafe
this is also a safeguard against data loss.

Well, with the above, at least I'm not experiencing network stalls when
copying GiB of data via Midnight Commander's sftp to my SSD until some
kernel-caused sync-ing is completed in the background.

I don't know if this will work for others, but if curious about any of
my other (sysctl)settings, they should be available for perusing
[here](https://github.com/howaboutsynergy/q1q/tree/0a2cd4ba658067140d3f0ae89a0897af54da52a4/OSes/archlinux/etc/sysctl.d)

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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/336652

Title:
  Poor system performance under I/O load

Status in Linux:
  Fix Released
Status in linux package in Ubuntu:
  Incomplete

Bug description:
  This bug seems to particularly affect the Dell Latitude D420, D430 and
  (from the kernel.org bug) at least the D830 laptop models; but others
  have been reported.

  Under I/O load, which need not be excessive - running usb-creator or
  even just checking one's email - the system performs remarkably
  poorly, far less than other laptop users see.  It can often take
  minutes to open a window, and sometimes the screen isn't repainted.
  Certainly most applications are "dimmed" by Compiz under I/O.

  It also appears to massively negatively affect boot performance, with
  one core spending its entire time in I/O wait - something we don't see
  elsewhere.

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