Still a problem, now on Unity8 in zesty desktop. An idle desktop spins the CPU constantly:

$ sudo strace -p `pidof unity8`
...
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25901, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\6\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 4) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\6\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 1) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25903, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25905, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25907, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\6\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 2) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25909, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 0) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\6\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25911, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25913, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\6\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 0) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25915, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 0) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\6\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25917, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25919, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25921, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 0) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\f\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25923, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25925, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)
futex(0x55a7fefd1e8c, FUTEX_WAIT_PRIVATE, 25927, NULL) = 0
futex(0x55a7fefd1e60, FUTEX_WAKE_PRIVATE, 1) = 0
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 0) = 1 ([{fd=4, revents=POLLIN}])
read(4, "\f\0\0\0\0\0\0\0", 16)         = 8
poll([{fd=4, events=POLLIN}, {fd=42, events=POLLIN}, {fd=44, events=POLLIN}, {fd=60, events=POLLIN}, {fd=68, events=POLLIN}, {fd=80, events=POLLIN}, {fd=82, events=POLLIN}, {fd=84, events=POLLIN}, {fd=86, events=POLLIN}, {fd=88, events=POLLIN}], 10, 5) = 0 (Timeout)