From: Vladislav Bolkhovitin <vst-d+Crzxg7Rs0@public.gmane.org>
To: Chris Worley <worleys-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
scst-devel
<scst-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Subject: Re: [Scst-devel] Adjusting minimum packet size or "wait to merge requests" in SRP
Date: Thu, 29 Oct 2009 21:30:41 +0300 [thread overview]
Message-ID: <4AE9DF51.9020707@vlnb.net> (raw)
In-Reply-To: <f3177b9e0910281147u5a47f75ao8bbe156d5b04969c-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
Chris Worley, on 10/28/2009 09:47 PM wrote:
> It appears that SRP tries to coalesce and fragment initiator I/O
> requests into 64KB packets, as that looks to be the size requested
> to/from the device on the target side (and the I/O scheduler is
> disabled on the target).
>
> Is there a way to control this, where no coalescing occurs when
> latency is an issue and requests are small, and no fragmentation
> occurs when requests are large?
>
> Or, am I totally wrong in my assumption that SRP is coalescing/fragmenting data?
You can at any time see size of requests you are receiving on the target
side by either enabling "scsi" logging (hopefully, you know how to do
it) or by looking in /proc/scsi_tgt/sgv. In the latter file you will see
general statistics for power of 2 allocations, i.e. request for 10K will
increase 16K row.
Vlad
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prev parent reply other threads:[~2009-10-29 18:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-28 18:47 Adjusting minimum packet size or "wait to merge requests" in SRP Chris Worley
[not found] ` <f3177b9e0910281147u5a47f75ao8bbe156d5b04969c-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-28 19:14 ` Bart Van Assche
[not found] ` <e2e108260910281214y5e3b5f4u24438986672e81b3-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-28 19:38 ` Chris Worley
[not found] ` <f3177b9e0910281238n1e53653eq3e667010caf8e745-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-28 19:58 ` David Dillow
[not found] ` <1256759902.3544.9.camel-FqX9LgGZnHWDB2HL1qBt2PIbXMQ5te18@public.gmane.org>
2009-10-28 20:25 ` Chris Worley
[not found] ` <f3177b9e0910281325i5ef5ce86u758ed665329232f2-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-10-28 21:05 ` David Dillow
2009-10-28 19:51 ` Roland Dreier
2009-10-29 18:30 ` Vladislav Bolkhovitin [this message]
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