Date: Mon, 28 Aug 2006 19:56:22 +1000 From: Peter Jeremy <peterjeremy@optushome.com.au> To: "Jin Guojun [VFFS]" <j_guojun@lbl.gov> Cc: freebsd-performance@freebsd.org, hardware@freebsd.org Subject: Re: reduce interrupt rate for CD/DVD drive(r) Message-ID: <20060828095622.GC747@turion.vk2pj.dyndns.org> In-Reply-To: <44F22CB9.9040100@lbl.gov> References: <44F22CB9.9040100@lbl.gov>
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--wULyF7TL5taEdwHz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, 2006-Aug-27 16:37:29 -0700, Jin Guojun [VFFS] wrote: >I have difficulty to get CD/DVD write speed above 1.6MB/s (10x for CD,=20 >or 1.1x for DVD). >The problem seems to be the interrupt rate is high (70-80% of CPU) for=20 >CD/DVD drive(r). Your drive is probably in PIO4 mode (due to there being bugs in the UDMA implementation on many drives). Check hw.ata.atapi_dma and "atacontrol mode acd0". You may find you can change to WDMA2 mode which will significantly reduce the interrupt and CPU load. You will need to do some experimenting with your drives to see what works for you. --=20 Peter Jeremy --wULyF7TL5taEdwHz Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFE8r3G/opHv/APuIcRAhEEAJ4oSVUSRiD+7eisBUxO0No/PQlqugCgilsx 1D2NcxEEb5CM3fW6DnQ65kM= =mleA -----END PGP SIGNATURE----- --wULyF7TL5taEdwHz--
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