KSE system scope vs non system scope threads
Christopher M. Sedore
cmsedore at maxwell.syr.edu
Sat Nov 29 16:54:21 PST 2003
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.
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.
If there is a canonical document that describes all this, a pointer would be very welcome.
-Chris
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