Date: Thu, 03 Sep 2009 17:54:44 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Scott Long <scottl@samsco.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r196777 - head/sys/dev/ahci Message-ID: <4A9FD8B4.2080605@FreeBSD.org> In-Reply-To: <1872D962-9297-4C45-9F73-4BB823C49D74@samsco.org> References: <200909031237.n83CbIgk032551@svn.freebsd.org> <1872D962-9297-4C45-9F73-4BB823C49D74@samsco.org>
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Scott Long wrote: > In this case, set maxio to 64k, not 127.5k. You'll typically get much > better i/o performance out of two 64k transfers > than you will out of one 127.k transfer and one 512 bytes transfer, > which is what the block layer will give you if > you try to send 128k. Couldn't it be somehow handled on that level? Limiting maxio from 127.5K to 64K is also a penalty for requests with length in that range. It would be nice if every level would do it's own job. > On Sep 3, 2009, at 6:37 AM, Alexander Motin wrote: >> Author: mav >> Date: Thu Sep 3 12:37:17 2009 >> New Revision: 196777 >> URL: http://svn.freebsd.org/changeset/base/196777 >> >> Log: >> ATI SB600 can't handle 256 sectors transfers with FPDMA (NCQ). >> >> MFC after: 3 days >> >> Modified: >> head/sys/dev/ahci/ahci.c >> >> Modified: head/sys/dev/ahci/ahci.c >> ============================================================================== >> >> --- head/sys/dev/ahci/ahci.c Thu Sep 3 10:06:37 2009 (r196776) >> +++ head/sys/dev/ahci/ahci.c Thu Sep 3 12:37:17 2009 (r196777) >> @@ -1942,6 +1942,9 @@ ahciaction(struct cam_sim *sim, union cc >> cpi->protocol = PROTO_ATA; >> cpi->protocol_version = PROTO_VERSION_UNSPECIFIED; >> cpi->maxio = MAXPHYS; >> + /* ATI SB600 can't handle 256 sectors with FPDMA (NCQ). */ >> + if (pci_get_devid(device_get_parent(dev)) == 0x43801002) >> + cpi->maxio = min(cpi->maxio, 255 * 512); >> cpi->ccb_h.status = CAM_REQ_CMP; >> xpt_done(ccb); >> break; > -- Alexander Motin
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