Date: Sun, 28 Nov 1999 19:21:00 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: "Daniel M. Eischen" <eischen@vigrid.com> Cc: Julian Elischer <julian@whistle.com>, arch@freebsd.org Subject: Re: Threads stuff Message-ID: <199911290321.TAA48755@apollo.backplane.com> References: <Pine.BSF.4.10.9911281515150.544-100000@current1.whistle.com> <3841CFB4.F5B9A2BD@vigrid.com> <199911290133.RAA47395@apollo.backplane.com> <3841EFF2.667F105@vigrid.com>
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:
:Matthew Dillon wrote:
:>
:> :If the kernel is going to automatically complete KSEs, then I would only
:> :do it when new KSEs block or when the process is resumed. The UTS is timing
:> :the current thread, so you don't want to do work for other threads while
:> :the UTS is going to count it against the currently running thread. If the
:> :kernel is not automatically completing the KSEs, then the UTS can be notified
:> :of unblocked KSEs at any time.
:>
:> The kernel *must* complete blocked KSE's or you run into a thousand
:> potential system deadlock situations. We have no choice there.
:
:The question is whether the kernel completes the KSEs automatically without
:direction from the UTS, or if the UTS is informed of the unblocking and later
:chooses to direct the kernel to complete the KSEs. The KSEs _will_ be
:completed, it's just who is directly responsible for their being completed.
:
:Dan Eischen
:eischen@vigrid.com
The kernel must be able to complete the KSEs without UTS intervention
or we risk seriously destabilizing our system.
The completion of the KSEs does not necessarily have to wake the
underlying thread up on return to user mode - that could be done
through notification of the UTS. Or the UTS could simply flag the
kernel that the underlying KSE can wake up the thread automatically
(which I recommend as the default).
-Matt
Matthew Dillon
<dillon@backplane.com>
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