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The default 1MB RDMA chunk size causes slow live migration because each chunk triggers a write_flush (ibv_post_send). For 8GB RAM, 1MB chunk size produces ~15000 flushes vs ~3700 with 1024MB chunk size. Add x-rdma-chunk-size parameter to configure the RDMA chunk size for faster migration. Usage: `migrate_set_parameter x-rdma-chunk-size 1024M` Performance with RDMA live migration of 8GB RAM VM: | x-rdma-chunk-size (B) | time (s) | throughput (MB/s) | |-----------------------|----------|-------------------| | 1M (default) | 37.915 | 1,007 | | 32M | 17.880 | 2,260 | | 1024M | 4.368 | 17,529 | Signed-off-by: Samuel Zhang <guoqing.zhang@amd.com> Acked-by: Markus Armbruster <armbru@redhat.com> Acked-by: Li Zhijian <lizhijian@fujitsu.com> Tested-by: Li Zhijian <lizhijian@fujitsu.com> Acked-by: Fabiano Rosas <farosas@suse.de> Acked-by: Peter Xu <peterx@redhat.com> Link: https://lore.kernel.org/r/20260427031401.3895523-1-guoqing.zhang@amd.com Signed-off-by: Peter Xu <peterx@redhat.com>