[8111] in linux-scsi channel archive
Re: scsi queue depth problem
daemon@ATHENA.MIT.EDU (Douglas Gilbert)
Tue Feb 15 07:46:33 2000
Message-ID: <38A94A7C.A4E27793@interlog.com>
Date: Tue, 15 Feb 2000 07:45:48 -0500
From: Douglas Gilbert <dgilbert@interlog.com>
MIME-Version: 1.0
To: "Ralston, Steve" <steve.ralston@lsil.com>
Cc: "'linux-scsi@vger.rutgers.edu'" <linux-scsi@vger.rutgers.edu>
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"Ralston, Steve" wrote:
>
> Anyone here experiencing limited queue depth?
>
> Thanks,
> -SteveR
>
> -----Original Message-----
> From: Alan Cox [SMTP:alan@lxorguk.ukuu.org.uk]
> Sent: Monday, February 14, 2000 8:12 PM
> To: steve.ralston@lsil.com
> Subject: Re: scsi queue depth problem
>
> Not off hand. linux-scsi@vger.rutgers.edu is the right place to ask - the
> scsi layer is being changed arouhnd a fair bit right now. You may be hitting
> a bug in it
>
> -----Original Message-----
> From: Ralston, Steve
> Sent: Monday, February 14, 2000 7:37 PM
> To: 'Alan Cox'
> Subject: scsi queue depth problem
>
> Hello Alan,
>
> I noticed something peculiar after updating from 2.3.42 kernel;
> I no longer seem able to get past max queue depth of ONE (!)
> now on the scsi IO path.
> I guess I never finished 2.3.43 build, but noticed this in both
> 2.3.44 and 2.3.45.
> Anything you know of that would be newly limiting me here?
Could you supply a bit more information:
- which adapter
- how were the hosts introduced (built in or insmod)
- how were the devices introduced (initial scan or add-single-device)
- how are you determining the queue length?
Perhaps you could load the sg driver and try:
$ cd /proc/scsi/sg
$ cat device_hdr devices
$ cat host_hdr hosts
and look at "qdepth" and "cpl" (commands per lun). There has
been a problem with the new MQ mid-level and advansys whereby
add-single-device gives you a device with a queue length of
0!
Doug Gilbert
-
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