Subject: RE: upcalls?
To: None <firstname.lastname@example.org, email@example.com>
From: Noriyuki Soda <firstname.lastname@example.org>
Date: 12/09/1999 20:06:44
> This might proove my ignorance, but I don't see the big win in having
> userland libraries fake more threads to the application than the kernel
> supports (with the one big exception beeing the kernel only supporting a
> single thread).
> Are there any results on the value of additional-userland-threads available,
> mesured in real world scenarios?
For example, please look at Fig.10, Fig.11 and Fig.12 of the following
technical report  (which is already refered in this discussion).
In this result, even if it is cpu intensive benchmark (i.e. there is
no i/o), performace order is:
^ - masuda-lab's thread based on asynchronous i/f
| - scheduler activations
| - traditional userland/kernel mixed thread
v - kernel only thread
You can see that masuda-lab's thread and scheduler activations are
far better than traditional U/K thread and K-only thread.
Shigekazu Inohara and Takashi Masuda.
"A framework for minimizing thread management overhead based on
asynchronous cooperation between user and kernel schedulers."
Technical Report 94-02, Department of Information Science,
Faculty of Science, University of Tokyo, Jan 1994.