From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Cc: Tom Talpey <tom-CLs1Zie5N5HQT0dZR+AlfA@public.gmane.org>,
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>,
Linux RDMA Mailing List
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH RFC 2/3] svcrdma: Use device rdma_read_access_flags
Date: Tue, 10 Nov 2015 16:55:51 -0700 [thread overview]
Message-ID: <20151110235551.GA12795@obsidianresearch.com> (raw)
In-Reply-To: <54CF0111-E9C4-4196-BF92-7E134A6A329A-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
On Tue, Nov 10, 2015 at 06:01:01PM -0500, Chuck Lever wrote:
> The current mechanism of statically choosing either FRMR or
> local DMA depending on the device is probably not adequate.
> Maybe we could post all the Read WRs via a single chain? Or
> stick with FRMR when the amount of data to read is significant.
Yes, those are the right ways to go..
IMHO, the break point for when it makes sense to switch from a RDMA
READ chain to a MR is going to be a RDMA core tunable. The performance
curve won't have much to do with the ULP.
But certainly, if a requests fits in the SG list then it should just
use the local dma lkey directly, and consider allocating an
appropriate S/G list size when creating the QP.
The special thing about iwarp becomes simply defeating the use of the
local dma lkey for RDMA READ.
Jason
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next prev parent reply other threads:[~2015-11-10 23:55 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-10 10:44 [PATCH RFC 0/3] Introduce device attribute rdma_read_access_flags Sagi Grimberg
[not found] ` <1447152255-28231-1-git-send-email-sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-11-10 10:44 ` [PATCH RFC 1/3] IB/core: Expose a device attribute for rdma_read access flags Sagi Grimberg
[not found] ` <1447152255-28231-2-git-send-email-sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-11-10 11:25 ` Christoph Hellwig
[not found] ` <20151110112537.GA8991-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 11:36 ` Sagi Grimberg
2015-11-10 11:51 ` Yann Droneaud
[not found] ` <1447156270.7089.3.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
2015-11-10 12:28 ` Sagi Grimberg
[not found] ` <5641E2D1.8070209-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2015-11-10 12:39 ` Sagi Grimberg
2015-11-10 12:36 ` Tom Talpey
[not found] ` <5641E4C9.7000206-CLs1Zie5N5HQT0dZR+AlfA@public.gmane.org>
2015-11-10 12:42 ` Sagi Grimberg
[not found] ` <5641E644.7080101-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-11-10 13:06 ` Christoph Hellwig
[not found] ` <20151110130648.GA10682-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 13:41 ` Christoph Hellwig
[not found] ` <20151110134147.GA12814-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 18:36 ` Jason Gunthorpe
[not found] ` <20151110183627.GJ12667-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-11-11 8:03 ` Christoph Hellwig
2015-11-11 9:07 ` Sagi Grimberg
[not found] ` <56430542.5090008-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2015-11-11 10:25 ` Christoph Hellwig
2015-11-10 18:06 ` Jason Gunthorpe
2015-11-10 18:01 ` Jason Gunthorpe
[not found] ` <20151110180156.GE12667-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-11-11 8:08 ` Christoph Hellwig
[not found] ` <20151111080837.GA14662-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-11 9:09 ` Sagi Grimberg
[not found] ` <564305AF.3020903-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2015-11-11 10:26 ` Christoph Hellwig
2015-11-10 10:44 ` [PATCH RFC 2/3] svcrdma: Use device rdma_read_access_flags Sagi Grimberg
[not found] ` <1447152255-28231-3-git-send-email-sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-11-10 11:38 ` Christoph Hellwig
[not found] ` <20151110113839.GA32523-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 11:42 ` Sagi Grimberg
2015-11-10 17:03 ` Chuck Lever
2015-11-10 11:41 ` Christoph Hellwig
[not found] ` <20151110114145.GA2810-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 11:46 ` Sagi Grimberg
[not found] ` <5641D920.5000409-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-11-10 12:04 ` Christoph Hellwig
[not found] ` <20151110120432.GA8230-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 14:34 ` Chuck Lever
[not found] ` <F60E8BA6-D728-44E4-9331-0C23AB96E634-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2015-11-10 15:16 ` Tom Talpey
2015-11-10 18:25 ` Jason Gunthorpe
[not found] ` <20151110182546.GI12667-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-11-10 21:00 ` Tom Talpey
[not found] ` <56425AFB.30202-CLs1Zie5N5HQT0dZR+AlfA@public.gmane.org>
2015-11-10 21:17 ` Jason Gunthorpe
[not found] ` <20151110211716.GA21631-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-11-10 21:30 ` Tom Talpey
[not found] ` <564261EF.4000008-CLs1Zie5N5HQT0dZR+AlfA@public.gmane.org>
2015-11-10 23:01 ` Chuck Lever
[not found] ` <54CF0111-E9C4-4196-BF92-7E134A6A329A-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2015-11-10 23:55 ` Jason Gunthorpe [this message]
[not found] ` <20151110235551.GA12795-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-11-11 8:07 ` Christoph Hellwig
2015-11-11 9:28 ` Sagi Grimberg
[not found] ` <56430A20.6040600-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2015-11-11 16:19 ` Chuck Lever
[not found] ` <D4228973-6DFA-4181-9848-41BFE8E75200-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2015-11-11 16:29 ` Sagi Grimberg
[not found] ` <56436CDB.6090305-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2015-11-11 20:50 ` Chuck Lever
2015-11-11 9:25 ` Sagi Grimberg
[not found] ` <56430972.8080703-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>
2015-11-11 17:39 ` Jason Gunthorpe
2015-11-11 8:02 ` Christoph Hellwig
[not found] ` <20151111080225.GA31508-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-11 17:23 ` Jason Gunthorpe
2015-11-10 16:12 ` Steve Wise
2015-11-10 10:44 ` [PATCH RFC 3/3] RDS_IW: " Sagi Grimberg
[not found] ` <1447152255-28231-4-git-send-email-sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-11-10 11:26 ` Christoph Hellwig
[not found] ` <20151110112638.GB8991-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 11:35 ` Sagi Grimberg
2015-11-10 11:31 ` [PATCH RFC 0/3] Introduce device attribute rdma_read_access_flags Christoph Hellwig
[not found] ` <20151110113141.GA23093-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2015-11-10 11:40 ` Sagi Grimberg
2015-11-10 16:18 ` Steve Wise
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