On 04/30/2014 04:58 PM, Doug Ledford wrote:
On 04/302014 Shirley Ma wrote:
On 04/30/2014 01:00 PM, Or Gerlitz wrote:
On Wed, Apr 30, 2014 at 10:47 PM, Chuck Lever
<chuck.lever@xxxxxxxxxx>
If I understood Yan, he is trying to use NFS/RDMA in guests
(kvm?). We
are pretty sure that is not working at the moment,
can you provide a short 1-2 liner why/what is broken there? the
only
thing which I can think of to be not-supported over mlx4 VFs is the
proprietary FMRs, but AFAIK, the nfs-rdma code doesn't even have a
mode which uses them, right?
I've created Xen guest on DomU. Dom0 PF works which has no mtts been
enabled, however DomU I hit this problem by just mounting the file
system:
mlx4_core 0000:00:04.0: Failed to allocate mtts for 66 pages(order 7)
mlx4_core 0000:00:04.0: Failed to allocate mtts for 4096 pages(order
12)
mlx4_core 0000:00:04.0: Failed to allocate mtts for 4096 pages(order
12)
RDMA microbenchmark perftest works ok. I enabled mtts scripts when
booting the Xen guest. cat /proc/mtrr:
What OS/RDMA stack are you using? I'm not familiar with any mtts
scripts, however I know there is an mtrr fixup script I wrote for
the RDMA stack in Fedora/RHEL (and so I assume it's in Oracle Linux
too, but I haven't checked). In fact, I assume that's the script
you are referring to based on the fact that your next bit of your
email cats the /proc/mtrr file. But I don't believe whether there
is an mtrr setting mixup or not that is should have any impact on
the mtts allocations in the driver. Even if your mtrr registers
were set incorrectly, the problem then becomes either A) a serious
performance bottleneck (in the case of Intel hardware that needs
write combining in order to get more than about 50MByte/s of
throughput on their cards) or B) failed operation because MMIO
writes to the card are being cached/write combined when they should
not be.
I suspect this is more likely Xen related than mtts/mtrr related.
Yes. That's the script I used. I wonder whether it's possible to disable
mtrr on DomU guest to debug this. I am new to Xen.
[root@ca-nfsdev1vm1 log]# cat /proc/mtrr
reg00: base=0x0f0000000 ( 3840MB), size= 128MB, count=1: uncachable
reg01: base=0x0f8000000 ( 3968MB), size= 64MB, count=1: uncachable
lspci -v
00:04.0 InfiniBand: Mellanox Technologies MT25400 Family [ConnectX-2
Virtual Function] (rev b0)
Subsystem: Mellanox Technologies Device 61b0
Physical Slot: 4
Flags: bus master, fast devsel, latency 0
Memory at f0000000 (64-bit, prefetchable) [size=128M]
Capabilities: [60] Express Endpoint, MSI 00
Capabilities: [9c] MSI-X: Enable+ Count=4 Masked-
Kernel driver in use: mlx4_core
Kernel modules: mlx4_core
I will need to find another machine to try KVM guest. Yan might hit a
different problem.
I have ConnectX-2, FW level is 2.11.2012. Yan has ConnectX-3, he
tried
it on KVM guest.
but that is a priority
to get fixed. Shirley has a lab set up and has been looking into
it.
Shirley
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