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Date:   Fri, 22 Jan 2021 07:58:00 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org
Subject: Re: [PATCH v1 2/2] svcrdma: DMA-sync the receive buffer in
 svc_rdma_recvfrom()
Message-ID: <20210122075800.GA113908@infradead.org>
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On Thu, Jan 21, 2021 at 03:53:12PM -0500, Chuck Lever wrote:
> The Receive completion handler doesn't look at the contents of the
> Receive buffer. The DMA sync isn't terribly expensive but it's one
> less thing that needs to be done by the Receive completion handler,
> which is single-threaded (per svc_xprt). This helps scalability.

On dma-noncoherent systems that have speculative execution (e.g. a lot
of ARM systems) it can be fairly expensive, so for those this a very
good thing.

Reviewed-by: Christoph Hellwig <hch@lst.de>