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Date:      Sat, 29 Nov 2003 19:54:19 -0500
From:      "Christopher M. Sedore" <cmsedore@maxwell.syr.edu>
To:        <threads@freebsd.org>
Subject:   KSE system scope vs non system scope threads
Message-ID:  <32A8B2CB12BFC84D8D11D872C787AA9A515DAE@EXCHANGE.forest.maxwell.syr.edu>

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=20
I have a fairly simple question about KSE threads: In a threaded program =
using KSE threads, what is the effective difference between a =
system-scope thread and a non-system-scope thread?  If I understand the =
KSE architecture correctly, there should not be a significant functional =
difference.  If my reading lead me to the right conclusion, at the =
nitty-gritty level, there are multiple KSE groups created with =
system-scope threads, as I understand it, meaning that the kernel =
scheduler actually does the scheduling work for system-scope threads, =
instead of the userland KSE scheduler.
=20
I ask this because I'm observing some behavior that I don't expect.  =
When running a threaded program with KSE and non-system-scope threads, I =
see performance degradation in my network traffic when I'm attempting to =
connect to remote hosts that are down.  Libthr doesn't see this =
degradation, and KSE with system-scope threads doesn't perform as well =
as libthr, but is much closer.
=20
If there is a canonical document that describes all this, a pointer =
would be very welcome.
=20
-Chris



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