Subject: Re: New features in NetBSD 2.0
To: SODA Noriyuki <>
From: Daniel de Kok <>
List: netbsd-docs
Date: 10/12/2004 21:20:08
On Tue, Oct 12, 2004 at 11:39:58PM +0900, SODA Noriyuki wrote:
> It's worth mentioning that one needs to set $PTHREAD_CONCURRENCY
> environment to the number of CPUs to make it actually run on multiple
> CPUs on NetBSD 2.0. Especially because there is no existing common
> practice about this environment variable on other OS, and this may be
> a temporary measure.
> (If our implementation is mature enough, the pthread library
>  must set $PTHREAD_CONCURRENCY to the number of CPUs by default.)

Good point. But I think it would not be a good idea to add this to
chap-whatsnew as a showcase of new features. But I think it would
be a very good idea to add this to chap-boot.

> 1. old buffer cache, which is used to cache filesystem metadata
>   (e.g. directories, i-nodes), are now dynamically allocated.


>   The old buffer cache now can use up to 15% of phyisical memory
>   by default.
>   On machines which only have really small memory, it may be
>   better to limit this upper bound by e.g. "sysctl -w vm.bufcache=5".


> 2. Many enhancements about user visible library functions.
>   e.g. native iconv(3), utmpx, SA_SIGINFO, POSIX 1003.1b semaphores, ...


> 3. Many scalability improvements. e.g. rbtree vmmap, splay tree
>   pvtree on i386 pmap, O(C) data insertion into socket buffers, etc...
>   (c.f.

Maybe this can be merged with 1 to a section named "Scalability 
improvements". I am willing to write this up for the book (if I
can find some more information). I am working on some 2.0-related
stuff anyway (chap-exinst for NetBSD 2.0), so I can add it to
my to-do list.

-- Daniel