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Date: Mon, 23 Aug 2010 12:07:23 -0400
Message-ID: <AANLkTinDY8hEABHaPsCC+3wGMCn0ZLcyfDa9U9jXJ3d4@mail.gmail.com>
Subject: Re: [Scst-devel] Fwd: Re: linuxcon 2010...
From: Chetan Loke <chetanloke@gmail.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: landman@scalableinformatics.com, James Bottomley <James.Bottomley@suse.de>,
        Vladislav Bolkhovitin <vst@vlnb.net>, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        scst-devel <scst-devel@lists.sourceforge.net>
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On Mon, Aug 23, 2010 at 11:11 AM, Bart Van Assche <bvanassche@acm.org> wrote:

>
> There is an important design difference between SCST and LIO: SCST by
> defaults creates multiple threads to process the I/O operations for a
> storage target, while LIO only creates a single thread per storage target.
> This makes SCST perform measurably faster.
>

Forget that. You could have discussed this if there were code reviews
or other mainline inclusion emails from James B. From what I have
heard, the decision was taken around 8-9 months back.
Would anyone like to either comment/validate/refute this please?  If
not then I would kindly request these guys to stop taking us for a
test drive. And also I'm not sure when was the last time James B.
bench-marked our scsi-stack. Even if I ACK in the xmit-path then I
can't push more than 100K IOPs. But other folks have re-engineered our
linux-scsi stack and from what I've heard they can push > 300K+ IOPs.
So I would just ignore performance discussion because I don't think
folks have done even simple lame experiments in the last 1 year. Or
may be I'm completely wrong and so please enlighten me so that I can
re-run the tests.


> Bart.
>
Chetan Loke
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