Date: Fri, 08 Sep 2006 18:30:57 +0900 From: Shunsuke SHINOMIYA <shino@fornext.org> To: freebsd-stable@freebsd.org Subject: reenable tagged queueing of VMware virtual disk. Message-ID: <20060908175132.EC4D.SHINO@fornext.org>
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Hi, Tagged queueing feature of a VMware virtual disk connected with SCSI has been disabled since the cam quirk was added. # this quirk is needed to find the drive by SCSI HA. I modified this quirk to allow tagged queueing while finding out causes of low disk performance. This modification improve the throughput of the disk I/O on VMware ESX Server 3, at least. (4MBps -> 18Mbps, by some easy measurements using dd). I think following modification to be applicable to RELENG_[456] and MAIN. I applied this patch to my RELENG_5 (virtual) box and do 'make -j4 buildworld' now and at present, the problem has not occurred. --- sys/cam/cam_xpt.c.orig Fri Sep 8 18:10:14 2006 +++ sys/cam/cam_xpt.c Fri Sep 8 17:43:57 2006 @@ -359,7 +359,7 @@ { /* Does not support other than LUN 0 */ { T_DIRECT, SIP_MEDIA_FIXED, "VMware*", "*", "*" }, - CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0 + CAM_QUIRK_NOLUNS, /*mintags*/2, /*maxtags*/255 }, thank you. -- Shunsuke SHINOMIYA <shino@fornext.org>
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