"Pause" doesn't fully stop VirtualBox => Fixed in SVN

[Artem S. Tashkinov]

"Pause" functionality in VirtualBox was intended to temporarily stop VM execution so that VirtualBox process consumed zero host CPU cycles.

Unfortunately it's not the case:

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  P COMMAND
12482 birdie    20   0  688m 619m 586m S  2.0 15.4   0:20.84 2 VirtualBox

I see consistent 2% CPU usage even though supposedly VirtualBox must be 100% idle.

Host OS: Fedora 14 i686, kernel 2.6.38-rc5 PAE, Intel Core i5 CPU, 4GB RAM
Guest OS: Windows XP SP3 32bit

VT-X:         enabled
Nested pages: enabled

[Artem S. Tashkinov]

strace system calls summary for 10 seconds:

% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 47.66    0.413477         779       531        79 futex
 23.49    0.203765         158      1290           poll
 15.37    0.133324       13332        10           ioctl
 12.68    0.109993         101      1088           rt_sigtimedwait
  0.77    0.006666        3333         2           restart_syscall
  0.03    0.000235           0      2078           clock_gettime
  0.01    0.000076           0      2101      1964 read
  0.00    0.000009           0       377           gettimeofday
  0.00    0.000000           0       201           write
  0.00    0.000000           0         3           sched_yield
  0.00    0.000000           0        99           send
  0.00    0.000000           0       262       101 recv
------ ----------- ----------- --------- --------- ----------------
100.00    0.867545                  8042      2144 total

[Artem S. Tashkinov]

Complete strace of VirtualBox process and all its threads for ten seconds

[Artem S. Tashkinov]

VirtualBox 4.1.6 has become even worse in this regard, CPU usage is over 3.3% in "Pause" mode.

[Frank Mehnert]

It seems that at least a part of the CPU load is induced by the GUI updating the indicator icons. Of course this has to be fixed.

[Frank Mehnert]

The fix will be part of the next maintenance release.

[Frank Mehnert]

Fix included in VBox 4.1.8.

[Artem S. Tashkinov]

It is indeed fixed, thank you!