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()
Date: Fri, 22 Jan 2021 07:58:00 +0000 [thread overview]
Message-ID: <20210122075800.GA113908@infradead.org> (raw)
In-Reply-To: <161126239239.8979.7995314438640511469.stgit@klimt.1015granger.net>
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>
next prev parent reply other threads:[~2021-01-22 7:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 20:52 [PATCH v1 0/2] Two small NFSD/RDMA scalability enhancements Chuck Lever
2021-01-21 20:53 ` [PATCH v1 1/2] svcrdma: Reduce Receive doorbell rate Chuck Lever
2021-01-21 20:53 ` [PATCH v1 2/2] svcrdma: DMA-sync the receive buffer in svc_rdma_recvfrom() Chuck Lever
2021-01-22 7:58 ` Christoph Hellwig [this message]
2021-01-22 14:37 ` Tom Talpey
2021-01-22 17:26 ` Christoph Hellwig
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