Re: [ewg] nfsrdma fails to write big file,

Tom Tucker
2010-02-25T00:02:01Z

Vu,

Based on the mapping code, it looks to me like the worst case is
RPCRDMA_MAX_SEGS * 2 + 1 as the multiplier.
However, I think in practice, due to the way that iov are built, the
actual max is 5 (frmr for head + pagelist plus invalidates for same plus
one for the send itself). Why did you think the max was 6?

Thanks,
Tom

Tom Tucker wrote:
> Vu,
>
> Are you changing any of the default settings? For example rsize/wsize,
> etc... I'd like to reproduce this problem if I can.
>
> Thanks,
>
> Tom
>
> Vu Pham wrote:
>
>> Tom,
>>
>> Did you make any change to have bonnie++, dd of a 10G file and vdbench
>> concurrently run & finish?
>>
>> I keep hitting the WQE overflow error below.
>> I saw that most of the requests have two chunks (32K chunk and
>> some-bytes chunk), each chunk requires an frmr + invalidate wrs;
>> However, you set ep->rep_attr.cap.max_send_wr = cdata->max_requests and
>> then for frmr case you do
>> ep->rep_atrr.cap.max_send_wr *=3; which is not enough. Moreover, you
>> also set ep->rep_cqinit = max_send_wr/2 for send completion signal which
>> causes the wqe overflow happened faster.
>>
>> After applying the following patch, I have thing vdbench, dd, and copy
>> 10g_file running overnight
>>
>> -vu
>>
>>
>> --- ofa_kernel-1.5.1.orig/net/sunrpc/xprtrdma/verbs.c 2010-02-24
>> 10:41:22.000000000 -0800
>> +++ ofa_kernel-1.5.1/net/sunrpc/xprtrdma/verbs.c 2010-02-24
>> 10:03:18.000000000 -0800
>> @@ -649,8 +654,15 @@
>> ep->rep_attr.cap.max_send_wr = cdata->max_requests;
>> switch (ia->ri_memreg_strategy) {
>> case RPCRDMA_FRMR:
>> - /* Add room for frmr register and invalidate WRs */
>> - ep->rep_attr.cap.max_send_wr *= 3;
>> + /*
>> + * Add room for frmr register and invalidate WRs
>> + * Requests sometimes have two chunks, each chunk
>> + * requires to have different frmr. The safest
>> + * WRs required are max_send_wr * 6; however, we
>> + * get send completions and poll fast enough, it
>> + * is pretty safe to have max_send_wr * 4.
>> + */
>> + ep->rep_attr.cap.max_send_wr *= 4;
>> if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr)
>> return -EINVAL;
>> break;
>> @@ -682,7 +694,8 @@
>> ep->rep_attr.cap.max_recv_sge);
>>
>> /* set trigger for requesting send completion */
>> - ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 /* - 1*/;
>> + ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/4;
>> +
>> switch (ia->ri_memreg_strategy) {
>> case RPCRDMA_MEMWINDOWS_ASYNC:
>> case RPCRDMA_MEMWINDOWS:
>>
>>
>>
>>
>>
>>
>>
>>> -----Original Message-----
>>> From: ewg-bounces-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org [mailto:ewg-
>>> bounces-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org] On Behalf Of Vu Pham
>>> Sent: Monday, February 22, 2010 12:23 PM
>>> To: Tom Tucker
>>> Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Mahesh Siddheshwar;
>>> ewg-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org
>>> Subject: Re: [ewg] nfsrdma fails to write big file,
>>>
>>> Tom,
>>>
>>> Some more info on the problem:
>>> 1. Running with memreg=4 (FMR) I can not reproduce the problem
>>> 2. I also see different error on client
>>>
>>> Feb 22 12:16:55 mellanox-2 rpc.idmapd[5786]: nss_getpwnam: name
>>> 'nobody'
>>> does not map into domain 'localdomain'
>>> Feb 22 12:16:55 mellanox-2 kernel: QP 0x70004b: WQE overflow
>>> Feb 22 12:16:55 mellanox-2 kernel: QP 0x6c004a: WQE overflow
>>> Feb 22 12:16:55 mellanox-2 kernel: QP 0x6c004a: WQE overflow
>>> Feb 22 12:16:55 mellanox-2 kernel: RPC: rpcrdma_ep_post: ib_post_send
>>> returned -12 cq_init 48 cq_count 32
>>> Feb 22 12:17:00 mellanox-2 kernel: RPC: rpcrdma_event_process:
>>> send WC status 5, vend_err F5
>>> Feb 22 12:17:00 mellanox-2 kernel: rpcrdma: connection to
>>> 13.20.1.9:20049 closed (-103)
>>>
>>> -vu
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: Tom Tucker [mailto:tom-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org]
>>>> Sent: Monday, February 22, 2010 10:49 AM
>>>> To: Vu Pham
>>>> Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Mahesh Siddheshwar;
>>>> ewg-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org
>>>> Subject: Re: [ewg] nfsrdma fails to write big file,
>>>>
>>>> Vu Pham wrote:
>>>>
>>>>
>>>>> Setup:
>>>>> 1. linux nfsrdma client/server with OFED-1.5.1-20100217-0600,
>>>>>
>>>>>
>>>> ConnectX2
>>>>
>>>>
>>>>> QDR HCAs fw 2.7.8-6, RHEL 5.2.
>>>>> 2. Solaris nfsrdma server svn 130, ConnectX QDR HCA.
>>>>>
>>>>>
>>>>> Running vdbench on 10g file or *dd if=/dev/zero of=10g_file bs=1M
>>>>> count=10000*, operation fail, connection get drop, client cannot
>>>>> re-establish connection to server.
>>>>> After rebooting only the client, I can mount again.
>>>>>
>>>>> It happens with both solaris and linux nfsrdma servers.
>>>>>
>>>>> For linux client/server, I run memreg=5 (FRMR), I don't see
>>>>>
>>>>>
>> problem
>>
>>
>>>> with
>>>>
>>>>
>>>>> memreg=6 (global dma key)
>>>>>
>>>>>
>>>>>
>>>>>
>>>> Awesome. This is the key I think.
>>>>
>>>> Thanks for the info Vu,
>>>> Tom
>>>>
>>>>
>>>>
>>>>
>>>>> On Solaris server snv 130, we see problem decoding write request
>>>>>
>>>>>
>> of
>>
>>
>>>> 32K.
>>>>
>>>>
>>>>> The client send two read chunks (32K & 16-byte), the server fail
>>>>>
>>>>>
>> to
>>
>>
>>>> do
>>>>
>>>>
>>>>> rdma read on the 16-byte chunk (cqe.status = 10 ie.
>>>>> IB_WC_REM_ACCCESS_ERROR); therefore, server terminate the
>>>>>
>>>>>
>>> connection.
>>>
>>>
>>>> We
>>>>
>>>>
>>>>> don't see this problem on nfs version 3 on Solaris. Solaris server
>>>>>
>>>>>
>>>> run
>>>>
>>>>
>>>>> normal memory registration mode.
>>>>>
>>>>> On linux client, I see cqe.status = 12 ie. IB_WC_RETRY_EXC_ERR
>>>>>
>>>>> I added these notes in bug #1919 (bugs.openfabrics.org) to track
>>>>>
>>>>>
>>> the
>>>
>>>
>>>>> issue.
>>>>>
>>>>> thanks,
>>>>> -vu
>>>>> _______________________________________________
>>>>> ewg mailing list
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>>>>> http://lists.openfabrics.org/cgi-bin/mailman/listinfo/ewg
>>>>>
>>>>>
>>>>>
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>
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