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From: Christoph Hellwig <hch@lst.de>
To: "Richard W.M. Jones" <rjones@redhat.com>
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	pbonzini@redhat.com
Subject: Re: Increased memory usage with scsi-mq
Date: Sat, 5 Aug 2017 10:44:36 +0200	[thread overview]
Message-ID: <20170805084436.GA14264@lst.de> (raw)
In-Reply-To: <20170804210035.GA10017@redhat.com>

On Fri, Aug 04, 2017 at 10:00:47PM +0100, Richard W.M. Jones wrote:
> I read your slides about scsi-mq and it seems like a significant
> benefit to large machines, but could the out of the box defaults be
> made more friendly for small memory machines?

The default inumber of queues and queue depth and thus memory usage is
set by the LLDD.

Try to reduce the can_queue value in virtio_scsi and/or make sure
you use the single queue variant in your VM (which should be tunable
in qemu).

  reply	other threads:[~2017-08-05  8:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-04 21:00 Increased memory usage with scsi-mq Richard W.M. Jones
2017-08-05  8:44 ` Christoph Hellwig [this message]
2017-08-05  9:27   ` Richard W.M. Jones
2017-08-05 13:39     ` Christoph Hellwig
2017-08-05 15:51       ` Richard W.M. Jones
2017-08-07 12:11         ` Paolo Bonzini
2017-08-07 12:27           ` Richard W.M. Jones
2017-08-07 13:07             ` Paolo Bonzini
2017-08-09 16:01               ` Christoph Hellwig
2017-08-09 16:50                 ` Paolo Bonzini
2017-08-10 12:22                   ` Richard W.M. Jones
2017-08-10 12:53                     ` Paolo Bonzini
2017-08-10 14:16                       ` Richard W.M. Jones
2017-08-10 14:30                         ` Paolo Bonzini
2017-08-10 15:40                           ` Richard W.M. Jones
2017-08-10 16:04                             ` Paolo Bonzini

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