From owner-freebsd-current@FreeBSD.ORG  Mon Oct 28 09:26:47 2013
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Date: Mon, 28 Oct 2013 13:28:44 +0400
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: freebsd-current@freebsd.org, freebsd-fs@freebsd.org
Subject: ZFS txg implementation flaw
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I can be wrong.
As I see ZFS cretate seperate thread for earch txg writing.
Also for writing to L2ARC.
As result -- up to several thousands threads created and destoyed per
second. And hundreds thousands page allocations, zeroing, maping
unmaping and freeing per seconds. Very high overhead.

In systat -vmstat I see totfr up to 600000, prcfr up to 200000.

Estimated overhead -- 30% of system time.

Can anybody implement thread and page pool for txg?