From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
Cc: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>,
"Nicholas A. Bellinger"
<nab-IzHhD5pYlfBP7FQvKIMDCQ@public.gmane.org>,
Parav Pandit
<pandit.parav-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Laurence Oberman
<loberman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH 2/5] IB/core: Add max_sge argument to rdma_rw_ctx_init()
Date: Tue, 28 Jun 2016 17:42:35 +0200 [thread overview]
Message-ID: <20160628154235.GA2843@lst.de> (raw)
In-Reply-To: <7fbd81ae-4b0d-4f8b-18ac-7efcf0dd4d61-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
On Tue, Jun 28, 2016 at 02:37:29PM +0200, Bart Van Assche wrote:
> The memory needed for QP buffers strongly depends on max_send_sge and
> max_recv_sge. Using a large value for max_send_sge and/or max_recv_sge for
> all drivers would increase the memory consumption for drivers that only
> submit RDMA requests with a low number of SG elements. Using a small value
> for max_send_sge and/or max_recv_sge would result in a performance decrease
> for drivers that benefit from large max_send_sge and/or max_recv_sge
> values. This is why I think that drivers should have the freedom to chose
> the max_send_sge and max_recv_sge values.
No problem with that - but please configure it on the QP as part of the
qp_init_attr structure instead of passing it to every RDMA READ/WRITE call.
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next prev parent reply other threads:[~2016-06-28 15:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 11:23 [PATCH 0/5] Make RDMA RW API SGE limit configurable Bart Van Assche
[not found] ` <419391ba-0c39-11ce-f249-84b428dc73d5-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 11:25 ` [PATCH 1/5] IB/core: Make rdma_rw_ctx_init() initialize all used fields Bart Van Assche
[not found] ` <91e53f7b-fdb6-bd66-ada6-982c641c2048-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 11:51 ` Christoph Hellwig
[not found] ` <20160628115105.GA28113-jcswGhMUV9g@public.gmane.org>
2016-06-28 13:04 ` Bart Van Assche
2016-06-28 11:26 ` [PATCH 2/5] IB/core: Add max_sge argument to rdma_rw_ctx_init() Bart Van Assche
[not found] ` <ce96b1f4-e9b9-31e2-f9d2-77e71f8bbcd1-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 11:52 ` Christoph Hellwig
[not found] ` <20160628115206.GB28113-jcswGhMUV9g@public.gmane.org>
2016-06-28 12:37 ` Bart Van Assche
[not found] ` <7fbd81ae-4b0d-4f8b-18ac-7efcf0dd4d61-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 15:42 ` Christoph Hellwig [this message]
[not found] ` <20160628154235.GA2843-jcswGhMUV9g@public.gmane.org>
2016-06-28 16:12 ` Bart Van Assche
2016-06-28 11:26 ` [PATCH 3/5] IB/isert: Limit the number of SG elements per work request Bart Van Assche
[not found] ` <885f39a6-9d75-9999-d582-e403f072bec1-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 14:28 ` Steve Wise
2016-06-28 14:58 ` Bart Van Assche
[not found] ` <74522811-15d7-41a2-d704-96083199454f-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 15:01 ` Steve Wise
2016-06-28 14:33 ` Steve Wise
2016-06-28 15:03 ` Bart Van Assche
[not found] ` <6e513522-6b06-d942-bddd-cc00f9a32f44-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 15:09 ` Steve Wise
2016-06-28 18:41 ` Bart Van Assche
[not found] ` <9e8c6a52-3bf9-6b3f-1f36-d77205cb3ee0-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 19:13 ` Steve Wise
2016-06-30 13:47 ` Bart Van Assche
2016-06-28 15:46 ` Christoph Hellwig
[not found] ` <20160628154618.GB2843-jcswGhMUV9g@public.gmane.org>
2016-06-28 16:11 ` Bart Van Assche
2016-06-28 11:28 ` [PATCH 4/5] IB/srpt: " Bart Van Assche
2016-06-28 11:29 ` [PATCH 5/5] IB/srpt: Simplify srpt_queue_response() Bart Van Assche
[not found] ` <8457ca4e-0359-687f-e078-76979adf54c3-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>
2016-06-28 11:52 ` Christoph Hellwig
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