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Re: Mach lack for frequent operations
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From: |
Thomas Bushnell BSG |
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Subject: |
Re: Mach lack for frequent operations |
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Date: |
Thu, 01 Dec 2005 11:03:54 -0800 |
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User-agent: |
Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) |
<ams@gnu.org> writes:
> - Fork is a hard cost operation.
>
> To get an idea how hard fork() is for us, Gianluca did a simple test,
> on GNU/Hurd he got 312 forks/second, and on the same machine but in
> GNU/Linux, he got 8170 forks/second.
Roland and I many years ago came to the conclusion that the primary
cost of fork is the cost of scanning and duplicating the port space of
the task correctly. We put on the task list the addition of a new
kernel RPC that would do the main job of that duplication in a single
context switch.
Thomas