Date: Fri, 5 Mar 1999 02:59:07 -0800 (PST) From: hokada@isl.melco.co.jp To: freebsd-gnats-submit@freebsd.org Subject: kern/10398: Tagged queueing makes IBM DCAS-34330 slow Message-ID: <19990305105907.8BB4D14DDC@hub.freebsd.org>
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>Number: 10398
>Category: kern
>Synopsis: Tagged queueing makes IBM DCAS-34330 slow
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: change-request
>Submitter-Id: current-users
>Arrival-Date: Fri Mar 5 03:00:01 PST 1999
>Closed-Date:
>Last-Modified:
>Originator: Hideaki Okada
>Release: 3.1-RELEASE
>Organization:
MITSUBISHI Electric
>Environment:
FreeBSD waikiki.isl.melco.co.jp 3.1-RELEASE FreeBSD 3.1-RELEASE #5: Sat Feb 20 01:25:27 JST 1999 hokada@waikiki.isl.melco.co.jp:/usr/src/sys/compile/WAIKIKI i386
>Description:
My IBM DCAS-34330 hard drive is connected to Adaptec AHA-2940 adapter,
and I found write performance is low.
Simple throughput measurement like 'dd if=/dev/zero of=test bs=64k count=1000'
shows ahout 3MB/s even though it should be 7-8MB/s .
However, there is no trouble on read performance.
Here is bonnie's results:
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
2.2.8R 100 6677 83.1 7542 22.8 3313 11.3 8519 93.4 7813 14.0 250.0 4.9
3.1R 100 7269 90.7 3199 10.5 2283 8.7 7450 95.7 7548 15.0 262.5 5.4
3.1R(*) 100 7376 91.3 6823 21.5 2628 9.3 6931 88.7 7469 14.3 240.6 4.7
(*) tagged queuing is turned off by modifying cam_xpt.c
>How-To-Repeat:
I reported this on FreeBSD-users-jp@jp.freebsd.org mailing list,
and the other report on this problem is posted.
Its configuration is:
IBM DCAS-34330W connected to AHA-2940UW
>Fix:
I put initializer of xpt_quirk_table at cam_xpt.c, and I got bonnie's result as reported above.
{
/*
* Slow when tagged queueing is enabled. (3MB/sec versus
* 8MB/sec.)
*/
{ T_DIRECT, SIP_MEDIA_FIXED, "IBM", "DCAS-34330", "S65A" },
/*quirks*/0, /*mintags*/0, /*maxtags*/0
},
>Release-Note:
>Audit-Trail:
>Unformatted:
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