From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Gabriele Svelto
<gabriele.svelto-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Steve Wise
<swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>,
dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH RFC] libibverbs: add ARM64 memory barrier macros
Date: Tue, 24 May 2016 11:22:50 -0600 [thread overview]
Message-ID: <20160524172250.GD8037@obsidianresearch.com> (raw)
In-Reply-To: <b4eb5c63-9f20-b927-ebc8-f8016accc93c-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
On Fri, May 20, 2016 at 11:44:14AM +0200, Gabriele Svelto wrote:
> On 19/05/2016 21:28, Jason Gunthorpe wrote:
> > Yes, we probably should have had a 'memcpy to wc' verbs helper that
> > did the best possible wc copy and prompt flush rather than the mess
> > with wc_wmb and open coded memcpy. IIRC there is some way to do this
> > with xmm non temporal cache line stores that is even better???
>
> Non-temporal stores will go straight to memory IIRC. With many modern
> HCAs being able to read data directly out of the last-level cache of the
> processor they could end up being a suboptimal choice.
We are not talking about memory backed write for DMA, but batching a
MMIO write into a 64 byte burst. non-temporal stores would seem to be
the best way to do that?
Jason
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next prev parent reply other threads:[~2016-05-24 17:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-18 21:16 [PATCH RFC] libibverbs: add ARM64 memory barrier macros Steve Wise
[not found] ` <20160518220302.81260E09E9-/5N3P9jjx0xzbRFIqnYvSA@public.gmane.org>
2016-05-18 22:28 ` Jason Gunthorpe
[not found] ` <20160518222857.GB23835-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2016-05-19 16:02 ` Steve Wise
2016-05-19 16:35 ` Steve Wise
2016-05-19 18:05 ` Jason Gunthorpe
[not found] ` <20160519180552.GA26130-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2016-05-19 18:54 ` Steve Wise
2016-05-19 19:28 ` Jason Gunthorpe
[not found] ` <20160519192805.GA32668-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2016-05-20 9:44 ` Gabriele Svelto
[not found] ` <b4eb5c63-9f20-b927-ebc8-f8016accc93c-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-05-24 17:22 ` Jason Gunthorpe [this message]
2016-05-19 20:14 ` Bart Van Assche
[not found] ` <573E1EC3.5000907-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-05-19 20:57 ` Jason Gunthorpe
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