Date: Wed, 25 Apr 2018 03:15:33 +0300
From: Greg V <greg@unrelenting.technology>
To: Steve Wills <swills@FreeBSD.org>
Cc: FreeBSD Current <freebsd-current@freebsd.org>
Subject: Re: zfskern{txg_thread_enter} thread using 100% or more CPU
Message-ID: <1524615333.3550.1@hraggstad.unrelenting.technology>
In-Reply-To: <eff00384-d35b-3690-d455-c381b123c70a@FreeBSD.org>
References: <eff00384-d35b-3690-d455-c381b123c70a@FreeBSD.org>
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On Wed, Apr 25, 2018 at 2:30 AM, Steve Wills <swills@FreeBSD.org> wrote:
> Hi,
>
> Recently on multiple systems running CURRENT, I've been seeing the
> system become unresponsive. Leaving top(1) running has lead me to
> notice that when this happens, the system is still responding to ping
> and top over ssh is still working, but no new processes can start and
> switching to other tasks doesn't work. In top, I do see pid 17,
> [zfskern{txg_thread_enter}] monopolizing both CPU usage and disk IO.
> Any ideas how to troubleshoot this? It doesn't appear to be a
> hardware issue.
Hi,
Do you have something writing to a gzip compressed dataset? You can use
the vfssnoop DTrace script from
https://forums.freebsd.org/threads/sharing-of-dtrace-scripts.32855/#post-181816
to see who's writing what.
I don't remember if it was exactly txg_thread_enter or whatever, but
both CPU and disk sounds a lot like heavily compressed writes.
In my case, the Epiphany browser was downloading a large malware
database to ~/.config/epiphany/gsb-threats.db :D
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