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From: "Steve Wise" <swise@opengridcomputing.com>
To: "'Chuck Lever'" <chuck.lever@oracle.com>,
	<linux-rdma@vger.kernel.org>, <linux-nfs@vger.kernel.org>
Subject: RE: [PATCH 10/10] svcrdma: Switch CQs from IB_POLL_SOFTIRQ to IB_POLL_WORKQUEUE
Date: Thu, 28 Apr 2016 10:59:47 -0500	[thread overview]
Message-ID: <00ec01d1a166$fd134650$f739d2f0$@opengridcomputing.com> (raw)
In-Reply-To: <20160428151550.13068.24199.stgit@klimt.1015granger.net>



> -----Original Message-----
> From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma-
> owner@vger.kernel.org] On Behalf Of Chuck Lever
> Sent: Thursday, April 28, 2016 10:16 AM
> To: linux-rdma@vger.kernel.org; linux-nfs@vger.kernel.org
> Subject: [PATCH 10/10] svcrdma: Switch CQs from IB_POLL_SOFTIRQ to
> IB_POLL_WORKQUEUE
> 
> Spread NFSD completion handling across CPUs, and replace
> BH-friendly spin locking with plain spin locks.
> 
> iozone -i0 -i1 -s128m -y1k -az -I -N
> 
> Microseconds/op Mode. Output is in microseconds per operation.
> 
> Before:
>               KB  reclen   write rewrite    read    reread
>           131072       1      51      51       43       43
>           131072       2      53      52       42       43
>           131072       4      53      52       43       43
>           131072       8      55      54       44       44
>           131072      16      62      59       49       47
>           131072      32      72      69       53       53
>           131072      64      92      87       66       66
>           131072     128     144     130       94       93
>           131072     256     225     216      146      145
>           131072     512     485     474      251      251
>           131072    1024     573     540      514      512
>           131072    2048    1007     941      624      618
>           131072    4096    1672    1699      976      969
>           131072    8192    3179    3158     1660     1649
>           131072   16384    5836    5659     3062     3041
> 
> After:
>               KB  reclen   write rewrite    read    reread
>           131072       1      54      54       43       43
>           131072       2      55      55       43       43
>           131072       4      56      57       44       45
>           131072       8      59      58       45       45
>           131072      16      64      62       47       47
>           131072      32      76      74       54       54
>           131072      64      96      91       67       66
>           131072     128     148     133       97       97
>           131072     256     229     227      148      147
>           131072     512     488     445      252      255
>           131072    1024     582     534      511      540
>           131072    2048     998     988      614      620
>           131072    4096    1685    1679      946      965
>           131072    8192    3113    3048     1650     1644
>           131072   16384    6010    5745     3046     3053
> 
> NFS READ is roughly the same, NFS WRITE is marginally worse.
> 
> Before:
> GETATTR:
> 	242 ops (0%)
> 	avg bytes sent per op: 127
> 	avg bytes received per op: 112
> 	backlog wait: 0.000000
>  	RTT: 0.041322
>  	total execute time: 0.049587 (milliseconds)
> 
> After:
> GETATTR:
> 	242 ops (0%)
> 	avg bytes sent per op: 127
> 	avg bytes received per op: 112
> 	backlog wait: 0.000000
>  	RTT: 0.045455
>  	total execute time: 0.053719 (milliseconds)
> 
> Small op latency increased by 4usec.
> 


Hey Chuck, in what scenario or under what type of load do you expect this change to help performance?  I guess it would help as you scale out the number of clients and thus the number of CQs in use?   Do you do any measurements along these lines?

Stevo




WARNING: multiple messages have this Message-ID (diff)
From: "Steve Wise" <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
To: 'Chuck Lever'
	<chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: RE: [PATCH 10/10] svcrdma: Switch CQs from IB_POLL_SOFTIRQ to IB_POLL_WORKQUEUE
Date: Thu, 28 Apr 2016 10:59:47 -0500	[thread overview]
Message-ID: <00ec01d1a166$fd134650$f739d2f0$@opengridcomputing.com> (raw)
In-Reply-To: <20160428151550.13068.24199.stgit-Hs+gFlyCn65vLzlybtyyYzGyq/o6K9yX@public.gmane.org>



> -----Original Message-----
> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-
> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Chuck Lever
> Sent: Thursday, April 28, 2016 10:16 AM
> To: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Subject: [PATCH 10/10] svcrdma: Switch CQs from IB_POLL_SOFTIRQ to
> IB_POLL_WORKQUEUE
> 
> Spread NFSD completion handling across CPUs, and replace
> BH-friendly spin locking with plain spin locks.
> 
> iozone -i0 -i1 -s128m -y1k -az -I -N
> 
> Microseconds/op Mode. Output is in microseconds per operation.
> 
> Before:
>               KB  reclen   write rewrite    read    reread
>           131072       1      51      51       43       43
>           131072       2      53      52       42       43
>           131072       4      53      52       43       43
>           131072       8      55      54       44       44
>           131072      16      62      59       49       47
>           131072      32      72      69       53       53
>           131072      64      92      87       66       66
>           131072     128     144     130       94       93
>           131072     256     225     216      146      145
>           131072     512     485     474      251      251
>           131072    1024     573     540      514      512
>           131072    2048    1007     941      624      618
>           131072    4096    1672    1699      976      969
>           131072    8192    3179    3158     1660     1649
>           131072   16384    5836    5659     3062     3041
> 
> After:
>               KB  reclen   write rewrite    read    reread
>           131072       1      54      54       43       43
>           131072       2      55      55       43       43
>           131072       4      56      57       44       45
>           131072       8      59      58       45       45
>           131072      16      64      62       47       47
>           131072      32      76      74       54       54
>           131072      64      96      91       67       66
>           131072     128     148     133       97       97
>           131072     256     229     227      148      147
>           131072     512     488     445      252      255
>           131072    1024     582     534      511      540
>           131072    2048     998     988      614      620
>           131072    4096    1685    1679      946      965
>           131072    8192    3113    3048     1650     1644
>           131072   16384    6010    5745     3046     3053
> 
> NFS READ is roughly the same, NFS WRITE is marginally worse.
> 
> Before:
> GETATTR:
> 	242 ops (0%)
> 	avg bytes sent per op: 127
> 	avg bytes received per op: 112
> 	backlog wait: 0.000000
>  	RTT: 0.041322
>  	total execute time: 0.049587 (milliseconds)
> 
> After:
> GETATTR:
> 	242 ops (0%)
> 	avg bytes sent per op: 127
> 	avg bytes received per op: 112
> 	backlog wait: 0.000000
>  	RTT: 0.045455
>  	total execute time: 0.053719 (milliseconds)
> 
> Small op latency increased by 4usec.
> 


Hey Chuck, in what scenario or under what type of load do you expect this change to help performance?  I guess it would help as you scale out the number of clients and thus the number of CQs in use?   Do you do any measurements along these lines?

Stevo



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  reply	other threads:[~2016-04-28 15:59 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-28 15:14 [PATCH 00/10] NFS/RDMA server updates proposed for v4.7 Chuck Lever
2016-04-28 15:14 ` Chuck Lever
2016-04-28 15:14 ` [PATCH 01/10] svcrdma: Support IPv6 with NFS/RDMA Chuck Lever
2016-04-28 15:14   ` Chuck Lever
2016-04-28 15:14 ` [PATCH 02/10] svcrdma: Do not add XDR padding to xdr_buf page vector Chuck Lever
2016-04-28 15:14   ` Chuck Lever
2016-04-28 15:14 ` [PATCH 03/10] svcrdma: svc_rdma_put_context() is invoked twice in Send error path Chuck Lever
2016-04-28 15:14   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 04/10] svcrdma: Remove superfluous line from rdma_read_chunks() Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 05/10] svcrdma: Post Receives only for forward channel requests Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 06/10] svcrdma: Drain QP before freeing svcrdma_xprt Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 07/10] svcrdma: Eliminate code duplication in svc_rdma_recvfrom() Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 08/10] svcrdma: Generalize svc_rdma_xdr_decode_req() Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 09/10] svcrdma: Simplify the check for backward direction replies Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:15 ` [PATCH 10/10] svcrdma: Switch CQs from IB_POLL_SOFTIRQ to IB_POLL_WORKQUEUE Chuck Lever
2016-04-28 15:15   ` Chuck Lever
2016-04-28 15:59   ` Steve Wise [this message]
2016-04-28 15:59     ` Steve Wise
2016-04-28 16:15     ` Chuck Lever
2016-04-28 16:15       ` Chuck Lever

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