From: Tejun Heo <htejun@gmail.com>
To: Derek Taubert <taubert@geeks.org>
Cc: linux-ide@vger.kernel.org
Subject: Re: Bad write performance with libata-tj-stable-2.6.17.4-20060710, pcmcia based sata_sil24, PMP, and NCQ drive
Date: Tue, 29 Aug 2006 22:35:14 +0900 [thread overview]
Message-ID: <44F44292.30306@gmail.com> (raw)
In-Reply-To: <20060829075454.GA22899@geeks.org>
Derek Taubert wrote:
> The sd cache_type is set to "write back" for this drive. I suspect that
> the reads are coming from the block driver attempting to fill lines.
>
> # cat /sys/bus/scsi/devices/0:0:0:0/scsi_disk:0:0:0:0/cache_type
> write back
That's the cache inside the harddrive. To libata and SCSI, it's
(almost) transparent and doesn't cause such problems.
> Also, a problem here:
>
> # echo "none" > /sys/bus/scsi/devices/0:0:0:0/scsi_disk:0:0:0:0/cache_type
> echo: write error: invalid argument
>
> dmesg says:
>
> sda: Current: sense key: Illegal Request
> Additional sense: Invalid field in cdb
libata doesn't support that sysfs node (yet).
--
tejun
next prev parent reply other threads:[~2006-08-29 13:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-28 23:01 Bad write performance with libata-tj-stable-2.6.17.4-20060710, pcmcia based sata_sil24, PMP, and NCQ drive Derek Taubert
2006-08-29 2:39 ` Tejun Heo
2006-08-29 4:58 ` Derek Taubert
2006-08-29 7:54 ` Derek Taubert
2006-08-29 13:35 ` Tejun Heo [this message]
2006-08-29 13:27 ` Tejun Heo
2006-08-29 16:44 ` Derek Taubert
2006-08-29 21:24 ` Jeff Garzik
2006-09-01 13:32 ` Tejun Heo
2006-09-01 17:24 ` Derek Taubert
2006-09-02 5:34 ` Derek Taubert
2006-09-03 6:26 ` Derek Taubert
2006-09-03 19:03 ` Tejun Heo
2006-09-03 20:04 ` Derek Taubert
2006-09-28 22:07 ` Derek Taubert
2006-08-29 14:07 ` Greg Freemyer
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