[PATCH RFC 00/12] *** mulitple RDMA channels for migration ***

[Zhimin Feng]

From: fengzhimin <address@hidden>

Currently there is a single channel for RDMA migration, this causes
the problem that the network bandwidth is not fully utilized for
25Gigabit NIC. Inspired by the Multifd, we use two RDMA channels to
send RAM pages, which we call MultiRDMA.

We compare the migration performance of MultiRDMA with origin
RDMA migration. The VM specifications for migration are as follows:
- VM use 4k page;
- the number of VCPU is 4;
- the total memory is 16Gigabit;
- use 'mempress' tool to pressurize VM(mempress 8000 500);
- use 25Gigabit network card to migrate;

For origin RDMA and MultiRDMA migration, the total migration times of
VM are as follows:
+++++++++++++++++++++++++++++++++++++++++++++++++
|             | NOT rdma-pin-all | rdma-pin-all |
+++++++++++++++++++++++++++++++++++++++++++++++++
| origin RDMA |       18 s       |     23 s     |
-------------------------------------------------
|  MultiRDMA  |       13 s       |     18 s     |
+++++++++++++++++++++++++++++++++++++++++++++++++

For NOT rdma-pin-all migration, the multiRDMA can improve the
total migration time by about 27.8%.
For rdma-pin-all migration, the multiRDMA can improve the
total migration time by about 21.7%.

Test the multiRDMA migration like this:
'virsh migrate --live --rdma-parallel --migrateuri
rdma://hostname domain qemu+tcp://hostname/system'


fengzhimin (12):
  migration: Add multiRDMA capability support
  migration: Export the 'migration_incoming_setup' function           
             and add the 'migrate_use_rdma_pin_all' function
  migration: Create the multi-rdma-channels parameter
  migration/rdma: Create multiRDMA migration threads
  migration/rdma: Create the multiRDMA channels
  migration/rdma: Transmit initial package
  migration/rdma: Be sure all channels are created
  migration/rdma: register memory for multiRDMA channels
  migration/rdma: Wait for all multiRDMA to complete registration
  migration/rdma: use multiRDMA to send RAM block for rdma-pin-all mode
  migration/rdma: use multiRDMA to send RAM block for NOT rdma-pin-all
                  mode
  migration/rdma: only register the virt-ram block for MultiRDMA

 migration/migration.c |   55 +-
 migration/migration.h |    6 +
 migration/rdma.c      | 1320 +++++++++++++++++++++++++++++++++++++----
 monitor/hmp-cmds.c    |    7 +
 qapi/migration.json   |   27 +-
 5 files changed, 1285 insertions(+), 130 deletions(-)

-- 
2.19.1