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Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk re
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration |
Date: |
Sun, 21 Apr 2013 22:13:44 +0300 |
On Sun, Apr 21, 2013 at 01:19:17PM -0400, Michael R. Hines wrote:
> On 04/21/2013 10:17 AM, Michael S. Tsirkin wrote:
> >On Sun, Apr 21, 2013 at 03:19:21PM +0200, Paolo Bonzini wrote:
> >>Il 20/04/2013 19:02, Michael S. Tsirkin ha scritto:
> >>>>>I guess the opposite sense could be named 'x-rdma-pin-all'; default
> >>>>>false means to do chunk registration and release,
> >>>chunk release only happens after migration is complete unfortunately.
> >>>This means that eventually all initialized memory is pinned, regardless
> >>>of the setting (this is fixable but there's no plan to fix this, at this
> >>>point). So pin-all might be misleading to some.
> >>>
> >>>I agree 'chunk' is unnecessarily low level though.
> >>>The only difference ATM is pinning of uninitialized memory so I think a
> >>>better name would be 'x-rdma-pin-uninitialized' or some such.
> >>>
> >>x-rdma-pin-all is a better choice. x-rdma-pin-uninitialized is also too
> >>low level.
> >>
> >>Since this series is likely to miss 1.5 at this point, we could
> >>implement the unregistration part of the protocol in the destination.
> >>This way, any heuristic we add to the source will not break backwards
> >>compatibility.
> >>
> >>Paolo
> >To test, you'll have to implement it in the source too.
> >That's probably a good idea anyway, though doing this
> >efficiently might need more thought, and some of
> >the tricks I described earlier (pipelining,
> >registration cache) might be needed.
> >Though I'm curious what the performance impact would be
> >even without these tricks.
> >
>
> We already had a agreement to merge with ulimit -l + ibv_reg_mr() +
> ERROR + abort migration.
Not sure who is 'we' here, but for the record, I did not agree to merge
these patches, and I'm the wrong person to ask to merge them.
Juan is probably the right person to ask about merging them.
> We (IBM Research) will not commit to implementing this unless someone
> provides hard data showing it not to adversely effect migration performance.
>
> - Michael
--
MST
- [Qemu-devel] [PULL v4 06/11] rdma: new QEMUFileOps hooks, (continued)
- [Qemu-devel] [PULL v4 06/11] rdma: new QEMUFileOps hooks, mrhines, 2013/04/17
- [Qemu-devel] [PULL v4 01/11] rdma: export yield_until_fd_readable(), mrhines, 2013/04/17
- [Qemu-devel] [PULL v4 05/11] rdma: export qemu_fflush(), mrhines, 2013/04/17
- [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, mrhines, 2013/04/17
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Eric Blake, 2013/04/18
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael R. Hines, 2013/04/18
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael S. Tsirkin, 2013/04/20
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Paolo Bonzini, 2013/04/21
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael S. Tsirkin, 2013/04/21
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael R. Hines, 2013/04/21
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael R. Hines, 2013/04/21
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael S. Tsirkin, 2013/04/21
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael R. Hines, 2013/04/21
- Re: [Qemu-devel] [PULL v4 07/11] rdma: introduce capability for chunk registration, Michael R. Hines, 2013/04/21
[Qemu-devel] [PULL v4 09/11] rdma: send pc.ram, mrhines, 2013/04/17
[Qemu-devel] [PULL v4 11/11] rdma: add documentation, mrhines, 2013/04/17
[Qemu-devel] [PULL v4 08/11] rdma: core logic, mrhines, 2013/04/17