Re: Change in default vm_dirty_ratio

From: Nadia Derbey
Date: Thu Jun 21 2007 - 08:33:00 EST


Dave Jones wrote:
On Mon, Jun 18, 2007 at 04:47:11PM -0700, Andrew Morton wrote:

> Frankly, I find it very depressing that the kernel defaults matter. These
> things are trivially tunable and you'd think that after all these years,
> distro initscripts would be establishing the settings, based upon expected
> workload, amount of memory, number and bandwidth of attached devices, etc.

"This is hard, lets make it someone else's problem" shouldn't ever be the
answer, especially if the end result is that we become even more
dependant on bits of userspace running before the system becomes useful.

> Heck, there should even be userspace daemons which observe ongoing system
> behaviour and which adaptively tune these things to the most appropriate
> level.
> > But nope, nothing.

See the 'libtune' crack that people have been trying to get distros to
adopt for a long time.
If we need some form of adaptive behaviour, the kernel needs to be
doing this monitoring/adapting, not some userspace daemon that may
not get scheduled before its too late.


I'm wondering whether AKT I proposed a couple of months ago wouldn't be more appropriate (provided that we find the perfect heuristics to tune the dirty_ratio ;-) )
see thread http://lkml.org/lkml/2007/1/16/16

Regards,
Nadia


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