Marking Confirmed, I have experienced this too, and it seemed to start only when I updated about 24 hours ago.

Seems to be polling the sockets for each VM defined over and over without a 0 millisecond timeout. According to man 2 poll, a negative timeout is infinite, but it does not state that 0 is, so I can only assume that this is an error in some library call that should be specifying a timeout.

$ sudo strace -p 20110
Process 20110 attached - interrupt to quit
restart_syscall(<... resuming interrupted call ...>) = 1
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
recvfrom(28, "\0\0\0\4\0\240\0\363\0\20\0\v\0\0\0\7P\1\1\0\0\0\250\250\250\t\302>g\17\0\0"..., 4096, 0, NULL, NULL) = 131
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
poll([{fd=4, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
writev(4, [{"H\2\266\0uF`\5\207+`\5\20\0\v\0\240\0\363\0\0\30`\5\250\250\250\377\250\250\250\377"..., 728}, {NULL, 0}, {"", 0}], 3) = 728
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
poll([{fd=4, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
writev(4, [{"5\30\4\0v\335`\5%+`\5\20\0\v\0>\0\7\0uF`\5%+`\5\207+`\5"..., 52}, {NULL, 0}, {"", 0}], 3) = 52
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
poll([{fd=4, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
writev(4, [{"H\2\246\0uF`\5\207+`\5\20\0\n\0\260\0\364\0\0\30`\5\250\250\250\377\250\250\250\377"..., 664}, {NULL, 0}, {"", 0}], 3) = 664
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
poll([{fd=4, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
writev(4, [{"5\30\4\0w\335`\5%+`\5\20\0\n\0>\0\7\0uF`\5%+`\5\207+`\5"..., 52}, {NULL, 0}, {"", 0}], 3) = 52
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
poll([{fd=4, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
writev(4, [{"H\2\206\0uF`\5\207+`\5\20\0\10\0\220\0\366\0\0\30`\5\250\250\250\377\0\0\0\377"..., 536}, {NULL, 0}, {"", 0}], 3) = 536
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
poll([{fd=4, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=4, revents=POLLOUT}])
writev(4, [{"5\30\4\0x\335`\5%+`\5\20\0\10\0>\0\7\0uF`\5%+`\5\207+`\5"..., 52}, {NULL, 0}, {"", 0}], 3) = 52
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(4, 0x2e28f44, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=5, events=POLLIN}, {fd=4, events=POLLIN}, {fd=14, events=POLLIN|POLLPRI}, {fd=16, events=POLLIN|POLLPRI}, {fd=17, events=POLLIN|POLLPRI}, {fd=10, events=POLLIN|POLLPRI}, {fd=22, events=POLLIN}, {fd=19, events=POLLIN}, {fd=27, events=POLLIN}, {fd=26, events=POLLIN}, {fd=23, events=POLLIN}, {fd=18, events=POLLIN}], 12, 0) = 0 (Timeout)
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
rt_sigprocmask(SIG_SETMASK, [], [], 8)  = 0
sendto(28, "\3\1\0\0\0\0\2\200\1\340\3\1\0\0\0\0\2\200\1\340\3\1\0\0\0\0\2\200\1\340\3\1"..., 40, MSG_NOSIGNAL, NULL, 0) = 40
recvfrom(28, 0x416e1b8, 4096, 0, 0, 0)  = -1 EAGAIN (Resource temporarily unavailable)