Date: Mon, 20 Aug 2018 18:43:37 +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: <20180820184337.6e07e951@gumby.homeunix.com> In-Reply-To: <CAO3OKx_3nKDEKP_eii0QoC7DG57Y_KLrHxwJrV7r7UMRL%2BX5_A@mail.gmail.com> References: <CAO3OKx_3nKDEKP_eii0QoC7DG57Y_KLrHxwJrV7r7UMRL%2BX5_A@mail.gmail.com>
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On Mon, 20 Aug 2018 13:27:33 +0200 Ali Abdallah wrote: > Hello, > > I was just sorting randomly some jpg image files using: > > ls *.jpg | sort -R --random-source=/dev/urandom urandom is a sim-link to random, so --random-source=/dev/urandom does nothing useful > The above command never exited. Later I noticed that > one of my CPU is always running 100%. top -S reveals that it is > rand_harvestq kernel service. > > Is this is a bug? This occurs on 12-ALPHA1 and 11.2 It's a bit excessive > 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?
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