On Tuesday, March 18, 2003, at 07:47  AM, Pavel Cahyna wrote:

>> stable these days, although there are clearly problems with
>> trickle-sync that can lead to choppy performance in the face of a lot
>> of file system writes.
>
> Please, what's trickle-sync?

Trickle-sync is a method of "gradually" flushing data from the page 
cache to disk.  The idea is that instead of a big burst every minute or 
so, you get a constant "trickle" of data out to disk.

Unfortunately, the current code seems to no trickle very well; I often 
see a big burst (accompanied by a pause in application performance) 
when e.g. a vnode needs to be reclaimed (which requires that its 
buffers be flushed out to disk).  This big burst means that the vnode 
has a lot of dirty pages associated with it, implying that the data 
hasn't been trickle-sync'd out effectively.

         -- Jason R. Thorpe <thorpej@wasabisystems.com>