On Tue, Aug 02, 2011 at 03:45:51PM +0200, Shribman, Aidan wrote: > > From: Stefan Hajnoczi [mailto:stefa...@gmail.com] > > Sent: Thursday, July 07, 2011 11:23 AM > > To: Shribman, Aidan > > Cc: qemu-devel@nongnu.org; Anthony Liguori > > Subject: Re: [PATCH v2] XBRLE page delta compression for live > > migration of large memory apps > > > > Any thoughts on reducing the overhead and making xbrle on by default? > > XBRLE was replaced by XBZRLE which now runs word-wise and only attempts RLE > on zero sequences. In comparison to word-wise XBRLE it gives a more compact > encoding roughly 30% smaller in size. When compared to XOR+LZO or XOR+Snappy > encoding size is roughly 30% larger but XBZRLE is 2x-5x faster making it > ideal for fast in-line encoding such as required for live-migration. XBZRLE > demonstrated sustained speeds of about 1.6-2.2 GB/s per single core on a > 64bit Linux 2.6.35 kernel. > > For now I would not switch XBZRLE on by default as it effects the network > serialization format and would make the patched Qemu in-operable by default > with older Qemu versions. > > Full benchmark results are brought for several scenarios, defined according > to step in bytes between each two changed memoy areas (e.g. 1111 for the > sparse scenario) and the length in bytes of each changed area (e.g. 12 for > the SPARSE scenario) > > ========================================================== > Scenario SPARSE with diff segment of step 1111 len 12 > ========================================================== > xblzo: ENC{2.06s 997 MB/s 2.82%} DEC{1.40s 1462 MB/s 100.00%} .. ok > xbsnappy: ENC{1.82s 1122 MB/s 6.14%} DEC{1.67s 1225 MB/s 100.00%} .. ok > xbrle: ENC{9.28s 221 MB/s 3.08%} DEC{3.25s 630 MB/s 100.00%} .. ok > xbzrle: ENC{0.96s 2142 MB/s 3.55%} DEC{0.73s 2817 MB/s 100.00%} .. ok > > ========================================================== > Scenario MEDIUM with diff segment of step 701 len 33 > ========================================================== > xblzo: ENC{2.50s 820 MB/s 6.34%} DEC{1.37s 1492 MB/s 100.00%} .. ok > xbsnappy: ENC{2.25s 912 MB/s 9.27%} DEC{1.72s 1189 MB/s 100.00%} .. ok > xbrle: ENC{9.35s 219 MB/s 10.31%} DEC{3.36s 610 MB/s 100.00%} .. ok > xbzrle: ENC{1.03s 1994 MB/s 8.37%} DEC{0.73s 2809 MB/s 100.00%} .. ok > > ========================================================== > Scenario DENSE with diff segment of step 203 len 41 > ========================================================== > xblzo: ENC{4.08s 502 MB/s 21.37%} DEC{1.83s 1116 MB/s 100.00%} .. ok > xbsnappy: ENC{4.80s 426 MB/s 22.80%} DEC{2.15s 953 MB/s 100.00%} .. ok > xbrle: ENC{9.65s 212 MB/s 41.44%} DEC{3.70s 553 MB/s 100.00%} .. ok > xbzrle: ENC{1.23s 1666 MB/s 31.92%} DEC{0.84s 2441 MB/s 100.00%} .. ok > > ========================================================== > Scenario VERY-DENSE with diff segment of step 121 len 43 > ========================================================== > xblzo: ENC{5.59s 366 MB/s 32.29%} DEC{2.36s 866 MB/s 100.00%} .. ok > xbsnappy: ENC{6.74s 304 MB/s 33.46%} DEC{2.69s 762 MB/s 100.00%} .. ok > xbrle: ENC{9.84s 208 MB/s 72.78%} DEC{4.22s 486 MB/s 100.00%} .. ok > xbzrle: ENC{1.18s 1730 MB/s 54.92%} DEC{0.94s 2167 MB/s 100.00%} .. ok
xbrle -> xbzrle is a great improvement, nice! Stefan
