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From: Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
To: David Brean <David.Brean-UdXhSnd/wVw@public.gmane.org>
Cc: linux-rdma <linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: strong ordering for data registered memory
Date: Wed, 11 Nov 2009 09:57:23 -0800	[thread overview]
Message-ID: <adaskclvta4.fsf@roland-alpha.cisco.com> (raw)
In-Reply-To: <4AF9CACE.8070700-UdXhSnd/wVw@public.gmane.org> (David Brean's message of "Tue, 10 Nov 2009 15:19:26 -0500")


 > Some time ago there was an email sent to this group with the subject
 > "weak ordering for data registered memory".  I don't recall any action
 > resulting from this thread.  So, I have a question.  If a bit were
 > defined to specify "strong ordering", perhaps as a "access" flag (see
 > ibv_access_flags) and used with ibv_reg_mr(), would that be sufficient
 > for (1) client applications that need a HW "guarantee" of writing the
 > last byte of an RDMA last and (2) platform implementations that need
 > to deliver that feature?

What would happen if an application asked for strong ordering and the
adapter and/or platform is not capable of that?

Weak ordering is a bit easier to handle -- the app is saying "if you can
make things go faster, don't worry about ordering here" and a platform
where it doesn't matter can just ignore it.

 - R.
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  parent reply	other threads:[~2009-11-11 17:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-10 20:19 strong ordering for data registered memory David Brean
     [not found] ` <4AF9CACE.8070700-UdXhSnd/wVw@public.gmane.org>
2009-11-11 17:57   ` Roland Dreier [this message]
     [not found]     ` <adaskclvta4.fsf-BjVyx320WGW9gfZ95n9DRSW4+XlvGpQz@public.gmane.org>
2009-11-11 18:16       ` Richard Frank
     [not found]         ` <4AFAFF7A.4090602-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2009-11-11 22:11           ` David Brean
     [not found]             ` <4AFB3677.6050603-UdXhSnd/wVw@public.gmane.org>
2009-11-11 22:44               ` Richard Frank
     [not found]                 ` <4AFB3E6B.3080606-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2009-11-11 23:13                   ` Jason Gunthorpe
     [not found]                     ` <20091111231338.GZ1966-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2009-11-12  5:41                       ` Dave Olson
2009-11-12 20:43                       ` David Brean
2009-11-11 21:37       ` David Brean
     [not found]         ` <4AFB2EA5.4030804-UdXhSnd/wVw@public.gmane.org>
2009-11-11 23:06           ` Roland Dreier
     [not found]             ` <ada639gvezo.fsf-BjVyx320WGW9gfZ95n9DRSW4+XlvGpQz@public.gmane.org>
2009-11-12 20:42               ` David Brean
  -- strict thread matches above, loose matches on Subject: below --
2009-11-12 21:51 Caitlin Bestler

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