Hello! On Sat, Feb 18, 2006 at 03:40:48PM +0000, Constantine A. Murenin wrote: >I have a box with 512MB of RAM, which is running a snapshot from 2006-02-13.
>The box does not get used much, so most of the RAM stays still, i.e. >not used by the userland. >I am now quite surprised why OpenBSD does not use all of this RAM for >disc cache etc. Because nobody has submitted code that actually gets it right. There was code for unified VM/buffer cache in the tree once, but got reverted a few weeks later when it showed itself that there were significant problems with it. Just one "effect" you have to care for, on Linux (which *has* a unified VM/buffer cache system) we mkdir many directories (e.g. hashed buckets like squid uses them, just a few more, 256 * 256, to be precise). It was quite long (at least into the Linux 2.4 series) that that worked like this: mkdir completed quite fast until the memory was filled with dirty blocks, then the box *hung* completely until all the dirty blocks were actually written to disk. This isn't acceptable. And it's not acceptable for something like grep foo (a list of names of long files) pages out every program. Just two things where it shows how difficult it can be to get things right. It's much easier to get it right as it is in OpenBSD. >[...] Kind regards, Hannah.
