Hello, This is what mpstat typically looks like on a heavily loaded system building OS/Net with dmake configured to 16 concurrent tasks:
CPU minf mjf xcal intr ithr csw icsw migr smtx srw syscl usr sys
wt idl
0 561 0 16 383 94 171 13 13 82 0 521 12 43
0 45
1 667 0 22 107 2 150 14 12 83 0 571 15 35
0 50
2 655 0 15 166 108 107 14 12 159 0 564 15 42
0 43
3 643 0 17 109 5 151 15 12 82 0 542 15 35
0 50
4 683 0 17 102 2 139 15 12 79 0 570 15 35
0 50
5 675 0 18 101 2 140 14 12 79 0 569 15 34
0 50
6 714 0 14 100 2 129 15 12 78 0 584 16 34
0 51
7 622 0 23 93 3 127 14 11 73 0 521 15 34
0 51
Yes, the amount of idle and system time is *incredible*. Something must be
wrong. More than 20 running processes are reported by 'top' most of the time,
but at most 4 to 6 are on CPU at any given moment. :-(
This happens on a 64-bit VirtualBox (3.2.4 r62467) guest running on a Linux
host (4-core Core i7 (8 threads)). Setting a lower number of CPUs (such as 4)
does not help. Uniprocessor guests seem to work normally (with IO APIC
disabled).
I've read about bugs affecting the IO APIC performance under VirtualBox, but
all the reports say they are only relevant for 32-bit guests. This is a 64-bit
one.
I migrated the machine into a QEMU-KVM environment and performance got much
better, but still far from ideal. Instead of 15:35:50 (usr:sys:idl), I got
something like 70:30:0 (usr:sys:idl). (So there was no inexplicable idle time.
But still quite a lot of kernel overhead.)
Is this a known issue? Is there a solution? Could I diagnose it with DTrace
somehow? A piece of advice would be very helpful.
Andrej
P. S.
Unfortunately, OpenSolaris guests with IDE drives larger than 128 GiB cannot
currently run under QEMU-KVM. This is a description of the bug:
http://www.neuhalfen.name/2009/08/05/OpenSolaris_KVM_and_large_IDE_drives/
http://www.neuhalfen.name/2009/08/06/OpenSolaris_KVM_and_large_IDE_drives_II/
Virtual SATA drives don't suffer from this issue, but QEMU cannot emulate SATA
(so far). That's why I'd like to find out why the performance of OpenSolaris
under VirtualBox is so poor (and possibly find a workaround).
smime.p7s
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