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Date: Sat, 9 Oct 2004 18:07:34 -0400 (EDT)
From: Robert Watson <rwatson@FreeBSD.org>
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Subject: Re: cvs commit: src/sys/dev/random randomdev_soft.c
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On Sat, 9 Oct 2004, Robert Watson wrote:

>   - When reaping harvested entries from the queue, move all entries from
>     the queue at once, and when done with them, insert them all into a
>     thread-local queue for processing; then insert them all into the
>     empty fifo at once.  This reduces O(4n) mutex operations to O(2)
>     mutex operations per wakeup.

Right now we do a slightly harmful O(2N) walk of the records to move them
to a thread-local queue.  It would be very nice to have an O(1) tailq (and
other list) "move them all" operation to move all entries to a local head.
This would also be useful when dealing with other work queues in worker
threads, such as bio queues, etc.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Principal Research Scientist, McAfee Research