Comment 808 for bug 500069

Revision history for this message
In , iam (iam-linux-kernel-bugs) wrote :

Try Kernel 4.10.

>Improved writeback management
>
>Since the dawn of time, the way Linux synchronizes to disk the data written to
>memory by processes (aka. background writeback) has sucked. When Linux writes
>all that data in the background, it should have little impact on foreground
>activity. That's the definition of background activity...But for a long as it
>can be remembered, heavy buffered writers have not behaved like that. For
>instance, if you do something like $ dd if=/dev/zero of=foo bs=1M count=10k,
>or try to copy files to USB storage, and then try and start a browser or any
>other large app, it basically won't start before the buffered writeback is
>done, and your desktop, or command shell, feels unreponsive. These problems
>happen because heavy writes -the kind of write activity caused by the
>background writeback- fill up the block layer, and other IO requests have to
>wait a lot to be attended (for more details, see the LWN article).
>
>This release adds a mechanism that throttles back buffered writeback, which
>makes more difficult for heavy writers to monopolize the IO requests queue,
>and thus provides a smoother experience in Linux desktops and shells than what
>people was used to. The algorithm for when to throttle can monitor the
>latencies of requests, and shrinks or grows the request queue depth
>accordingly, which means that it's auto-tunable, and generally, a user would
>not have to touch the settings. This feature needs to be enabled explicitly in
>the configuration (and, as it should be expected, there can be regressions)