Date: Wed, 12 Dec 2012 12:43:36 +1100 From: Peter Jeremy <peter@rulingia.com> To: freebsd-emulation@freebsd.org Subject: FreeBSD/i386 guests using excessive host CPU Message-ID: <20121212014336.GD35245@server.rulingia.com>
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--xgyAXRrhYN0wYx8y Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable [Please copy me in any replies] My VPS provider will not offer 32-bit FreeBSD guests because they use excessive (ESXi) host CPU time. I have done some experiments using VirtualBox on my FreeBSD/amd64 8-stable host and see the same. An idle 32-bit FreeBSD 9 or 10 guest uses very roughly 25% more host CPU than an equivalent 64-bit guest. An idle 32-bit FreeBSD 8 guest uses very roughly 50% more host CPU than an equivalent 64-bit guest. This problem does not show up with Linux or Windows7 but occurs with both VirtualBox on AMD and ESXi on Intel CPUs. Since the problem shows up with different virtualisation environments and on different CPUs, this suggests this is a FreeBSD guest issue. My suspicion is that the cost of handling an interrupt on FreeBSD/i386 is higher than the cost on amd64 - and this is more obvious on 8.x because it doesn't use dynamic ticks. Has anyone else seen this behaviour and does anyone have any suggestions=20 for improving the FreeBSD/i386 performance. --=20 Peter Jeremy --xgyAXRrhYN0wYx8y Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlDH4UgACgkQ/opHv/APuIdq2wCfeAsSnlYjomuvEnIzyjPHSHn/ oNgAn2yRylMmq/BWEsEkH/lXruF7669Y =BcLd -----END PGP SIGNATURE----- --xgyAXRrhYN0wYx8y--
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