DragonFly BSD
DragonFly users List (threaded) for 2006-01
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Re: copying pkgsrc tree around jails on beefy machine - fast on 2nd iteration, a bit slower than first on 3rd iteration

From: Miguel Filipe <miguel.filipe@xxxxxxxxx>
Date: Fri, 6 Jan 2006 01:44:18 +0000

Hi all,

On 1/5/06, Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx> wrote:
> :
>     The kernel is fairly conservative with regards to the number of vnodes
>     it allows to be cached because the memory required to hold the vnodes
>     and related VM structures can exceed the kernel's own fairly limited
>     address space.  When doing copy operations on large numbers of small
>     files, the vnode limit will often be hit before the memory limit.
>     (When copying larger files the memory limit is hit before the vnode
>     limit).

thanks for that info.

btw, how's the address space split beetween on dragonfly?
On linux/x86 is kernel 1GB, app: 3GB
on windows/x86 is kernel 2GB, apps: 2GB, supposadly tunnable, but I
couldn't get the 1:3 split I needed on win2k nor winXP.
I don't know how's that on BSD systems...

Just has a reminder, kernel and apps don't share virtual address
space, but they somehow have this split because of performance issues
with flushing the TLB on every kernel call, I think where are also
some problems with some drivers memory mappings, PCI and DMA mappings
also, am I by any chance correct?


Miguel Sousa Filipe

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