From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH 13/17] scsi: push host_lock down into scsi_{host,target}_queue_ready
Date: Fri, 07 Feb 2014 11:32:02 +0100
Message-ID: <52F4B622.1070900@acm.org>
References: <20140205123930.150608699@bombadil.infradead.org>	 <20140205124021.286457268@bombadil.infradead.org>	 <1391705819.22335.8.camel@dabdike> <52F3C21F.70409@acm.org> <1391723900.14985.3.camel@haakon3.risingtidesystems.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Return-path: <linux-scsi-owner@vger.kernel.org>
Received: from smtp03.stone-is.org ([87.238.162.65]:44201 "EHLO
	smtpgw.stone-is.be" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org
	with ESMTP id S1751578AbaBGKcH (ORCPT
	<rfc822;linux-scsi@vger.kernel.org>); Fri, 7 Feb 2014 05:32:07 -0500
In-Reply-To: <1391723900.14985.3.camel@haakon3.risingtidesystems.com>
Sender: linux-scsi-owner@vger.kernel.org
List-Id: linux-scsi@vger.kernel.org
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>, Christoph Hellwig <hch@infradead.org>, Jens Axboe <axboe@kernel.dk>, linux-scsi@vger.kernel.org

On 02/06/14 22:58, Nicholas A. Bellinger wrote:
> Starting with a baseline using scsi_debug that NOPs REQ_TYPE_FS commands
> to measure improvements would be a better baseline vs. scsi_request_fn()
> existing code that what your doing above.
> 
> That way at least it's easier to measure specific scsi-core overhead
> down to the LLD's queuecommand without everything else in the way.

Running initiator and target workload on the same system makes initiator
and target code share CPUs and hence makes it hard to analyze which
performance change is caused by initiator optimizations and which
performance change is caused by interactions between initiator and
target workloads.

Bart.