Date: Tue, 15 Sep 2009 17:38:30 +1000 From: peterjeremy@acm.org To: Barney Cordoba <barney_cordoba@yahoo.com> Cc: freebsd-net@freebsd.org Subject: Re: [POLLING] strange interrupt/system load Message-ID: <20090915073830.GC48679@server.vk2pj.dyndns.org> In-Reply-To: <94372.57247.qm@web63906.mail.re1.yahoo.com> References: <4AACEF9E.90303@mail.ru> <94372.57247.qm@web63906.mail.re1.yahoo.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--bKyqfOwhbdpXa4YI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2009-Sep-13 07:19:24 -0700, Barney Cordoba <barney_cordoba@yahoo.com> wr= ote: >64bits must be faster than 32bits is patently misguided. My rule of=20 >thumb is that if I don't need 64bits for something, I avoid it. It's not quite that cut-and-dry. The 64-bit ISA is significantly different to the 32-bit ISA and has different subroutine calling conventions. Yes, you do need to lug 64-bit pointers around but the overall codesize is comparable (looking at /usr/bin and /lib suggests about a 5% increase in size going from i386 to amd64) - a lot of this is probably because amd64 has a 16-bit offset mode so there's much less need for 32-bit offsets. Having twice as many registers is a win in some areas (less spilling to memory) and a loss in others (more state to save/restore on a context switch). If performance is critical, it's probably worthwhile benchmarking both i386 and amd64 variants and seeing which works best for you. --=20 Peter Jeremy --bKyqfOwhbdpXa4YI Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.12 (FreeBSD) iEYEARECAAYFAkqvRHYACgkQ/opHv/APuIeIuACdHSMLn1nZ/m/H38sZTzDgE8Uv Y4IAn1G8CPnLW2h4IfeRvIXlmET+oMOn =vbdQ -----END PGP SIGNATURE----- --bKyqfOwhbdpXa4YI--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20090915073830.GC48679>