qemu/docs/xbzrle.txt

1 XBZRLE (Xor Based Zero Run Length Encoding)
4 Using XBZRLE (Xor Based Zero Run Length Encoding) allows for the reduction
5 of VM downtime and the total live-migration time of Virtual machines.
28 A zero run is represented by its length (in bytes).
29 A non zero run is represented by its length (in bytes) and the new data.
30 The run length is encoded using ULEB128 (http://en.wikipedia.org/wiki/LEB128)
38 zrun = length
40 nzrun = length byte...
42 length = uleb128 encoded integer
55 XBZRLE has a sustained bandwidth of 2-2.5 GB/s for typical workloads making it
56 ideal for in-line, real-time encoding such as is needed for live-migration.
71 encoded length 24
91 3. Set the XBZRLE cache size - the cache size is in MBytes and should be a
93     {qemu} migrate_set_parameter xbzrle-cache-size 256m
96     {qemu} migrate -d tcp:destination.host:4444
115 xbzrle cache miss: the number of cache misses to date - high cache-miss rate
120 (half a page).