83903 – Parallel startup hangs in busy wait (kernel dependent)

Bug 83903 - Parallel startup hangs in busy wait (kernel dependent)

Summary: Parallel startup hangs in busy wait (kernel dependent)

Status:	RESOLVED DUPLICATE of bug 69854

Alias:	None

Product:	Gentoo Linux
Classification:	Unclassified
Component:	[OLD] Core system (show other bugs)
Hardware:	All All

Importance:	High normal (vote)
Assignee:	Gentoo's Team for Core System packages

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Depends on:
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Reported:	2005-03-02 17:28 UTC by Ed Catmur
Modified:	2005-06-28 12:49 UTC (History)
CC List:	0 users

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Runtime testing required:	---

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Description Ed Catmur 2005-03-02 17:28:02 UTC

Parallel startup hangs at various points. (At least, if it doesn't hang, it's stalling for over 10 minutes.)

Investigation shows it is hanging in a busy wait at /lib/rcscripts/sh/rc-services.sh +622:

				# Wait until we have only one service running
				while [ "${count}" -gt 1 ]
				do
					count="$(jobs | tee /dev/stderr | grep -c "Running")"
				done

This does happen only on certain kernels; in my case the nitro series 2.6.11 release candidates. I imagine this is preemption related, or other desktop performance features. I am using the CFQ scheduler, if that's relevant.

Regardless, this busy wait is not good; even if it does not hang a system it is slowing down startup.

Would a "sleep 0.1" be acceptable?

Comment 1 Ed Catmur 2005-03-02 18:24:49 UTC

Hmm, the wait builtin is too sparse-featured to be useful here.

How about this hack:

        sleep 60 &
        trap "kill $!" SIGCHLD
        fg
        trap "" SIGCHLD

Comment 2 Ed Catmur 2005-03-02 19:30:13 UTC

Sorry, that should be

        sleep 60 &
        trap "kill $!" SIGCHLD
        fg
        trap - SIGCHLD

Comment 3 Ed Catmur 2005-06-28 12:49:42 UTC


*** This bug has been marked as a duplicate of 69854 ***