On 5/19/2022 6:04 AM, lizhijian@xxxxxxxxxxx wrote:
On 18/05/2022 11:41, Bob Pearson wrote:
-------- Forwarded Message --------
Subject: Re: Bug in pyverbs for test_qp_ex_rc_bind_mw
Date: Tue, 17 May 2022 22:41:08 -0500
From: Bob Pearson <rpearsonhpe@xxxxxxxxx>
To: Jason Gunthorpe <jgg@xxxxxxxxxx>, Zhu Yanjun <zyjzyj2000@xxxxxxxxx>, Edward Srouji <edwards@xxxxxxxxxx>, Leon Romanovsky <leon@xxxxxxxxxx>
On 5/17/22 21:57, Bob Pearson wrote:
test_qp_ex_rc_bind_mw has an error in that the new_rkey is computed from the old mr rkey and not the old mw rkey.
The following lines
mw = MW(server.pd, mw_type=e.IBV_MW_TYPE_2)
...
new_rkey = inc_rkey(server.mr.rkey)
server.qp.wr_bind_mw(mw, new_rkey, bind_info)
will compute a new rkey with the same index as mr and a key portion that is one larger than mr modulo 256.
This is passed to wr_bind_mw which expects a parameter with a new key portion of the mw (not the mr).
The memory windows implementation in rxe generates a random initial rkey for mw and for bind_mw it
checks that the new 8 bit key is different than the old key. Since the mr and mw are random wrt each other
we expect that the new key will match the old key approx 1 out of 256 test runs which will cause an error
which is just what I see.
The correct code should be
new_key = inc_rkey(<old mw.rkey>)
which will guarantee that it is always different than the previous key. The problem is I can't figure out
how to compute the rkey from the mw or I would submit a patch.
Bob
If in test_qpex.py I type
print("mw = ", mw)
print("mr = ", self.server.mr)
I get
mw = MW:
Rkey : 12345678
Handle : 4
MW Type : IBV_MW_TYPE_2
mr = MR
lkey : 432134
rkey : 432134
length : 1024
buf : 9403912345678
handle : 2
The difference is the colon ':' after MW and caps.
For the difference, just post a RP to make them identical: https://github.com/linux-rdma/rdma-core/pull/1175
Thanks for the adjustment.
Thanks
Zhijian
I can refer to mr.rkey as self.server.mr.rkey no problem
but mw.Rkey doesn't work. Neither does mw.rkey or anything else I have thought of.
mw.rkey should work... I noticed that you've already figured that out
and sent a patch.
We expose the MW rkey in pyverbs (within the cython code).
If you still have an issue with it please let me know.
I hate python. Just hate it.
Don't hate the game, hate the player :) (in this case).
Bob
