From owner-freebsd-hackers@freebsd.org  Mon Aug 20 18:35:14 2018
Return-Path: <owner-freebsd-hackers@freebsd.org>
Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id BB33B107873D
 for <freebsd-hackers@mailman.ysv.freebsd.org>;
 Mon, 20 Aug 2018 18:35:14 +0000 (UTC)
 (envelope-from rwmaillists@googlemail.com)
Received: from mail-wm0-x241.google.com (mail-wm0-x241.google.com
 [IPv6:2a00:1450:400c:c09::241])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (Client CN "smtp.gmail.com",
 Issuer "Google Internet Authority G3" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id 3BF937B4FA
 for <freebsd-hackers@freebsd.org>; Mon, 20 Aug 2018 18:35:14 +0000 (UTC)
 (envelope-from rwmaillists@googlemail.com)
Received: by mail-wm0-x241.google.com with SMTP id t25-v6so478416wmi.3
 for <freebsd-hackers@freebsd.org>; Mon, 20 Aug 2018 11:35:14 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:date:from:to:subject:message-id:in-reply-to
 :references:mime-version:content-transfer-encoding;
 bh=d4pW4lr1C6jbxGCGvmpd2uCmfgFXAarFkutDBnmX6tw=;
 b=AWgSLBnSjsGhZCFeZajrr9KchdUR4KzrjQcty4t7csUwT8J+sUpgywzWNZZH6SjwFE
 R4YXnDQuQIyNLV3ak4CgkREL06mNmeXRf6Aqqn7bIL1uMtnrmqGu5FNiwmndEQndoKyL
 Xt5qmKurEL98m1lvkM8xdGEBxlkO5ZG5Nt/vQM757DYV3Ajnd2RzrsuJ7/rIiUVtka27
 OiQk7hoVBIf759FhdEk0wcP0KLowVLm0oVtcQmj9tFcx5mh1J5Ev59mm/TTpPpm1Q1Fg
 3gOczobg+WroN7bpQYyOMbsBz/rUsfAGDlYhuGWiz7YCFuSZQSu+8RDJBcIyg7gJ/gj+
 HT5w==
X-Gm-Message-State: AOUpUlGCaT/keiljPiB8KX1lRr6ETae2zg68wF8nmtjioYIk+7Wxaxpc
 TJ7qefj5kt5Y3PYTojUlyxSnVXA9u48=
X-Google-Smtp-Source: AA+uWPxY3O3LrRZKCSXLvJfrLDFyNPyoKQAInb2csysBcbxSB84+55Y+fw/MfiiRbVsNqErBYlly9g==
X-Received: by 2002:a1c:1943:: with SMTP id
 64-v6mr25565846wmz.89.1534790113044; 
 Mon, 20 Aug 2018 11:35:13 -0700 (PDT)
Received: from gumby.homeunix.com ([90.210.182.138])
 by smtp.gmail.com with ESMTPSA id g133-v6sm332965wmf.44.2018.08.20.11.35.11
 for <freebsd-hackers@freebsd.org>
 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256);
 Mon, 20 Aug 2018 11:35:12 -0700 (PDT)
Date: Mon, 20 Aug 2018 19:35:09 +0100
From: RW <rwmaillists@googlemail.com>
To: freebsd-hackers@freebsd.org
Subject: Re: rand_harvestq high cpu usage when /dev/urandom is used
Message-ID: <20180820193509.19545f40@gumby.homeunix.com>
In-Reply-To: <20180820184337.6e07e951@gumby.homeunix.com>
References: <CAO3OKx_3nKDEKP_eii0QoC7DG57Y_KLrHxwJrV7r7UMRL+X5_A@mail.gmail.com>
 <20180820184337.6e07e951@gumby.homeunix.com>
X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; amd64-portbld-freebsd11.1)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.27
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
 <freebsd-hackers.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers/>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 20 Aug 2018 18:35:14 -0000

On Mon, 20 Aug 2018 18:43:37 +0100
RW wrote:


> > Also, I read on
> > https://lists.freebsd.org/pipermail/freebsd-current/2013-November/046683.html
> > someone saying that sysctls to turn off harvesting is documented in
> > random(6)
> > <https://www.freebsd.org/cgi/man.cgi?query=random&sektion=6&manpath=freebsd-release-ports>.
> > I had a look at that document, but wasn't clear to me how to turn it
> > off. I tried to play with the mask,
> > but nothing.  
>  
> what happens if you set the mask to zero?

I just tried that and it didn't make any difference, which is strange.