Re: high load with win7 & usb tablet

[Michael Tokarev <mjt@tls.msk.ru>]

10.09.2010 18:56, Avi Kivity пишет:
>  On 09/10/2010 05:47 PM, Michael Tokarev wrote:
>> 10.09.2010 16:50, Avi Kivity wrote:
>> []
>>>> During this shot, host CPU was about 30..35% in use - higher
>>>> than usual 25%, but I guess it's due to perfmon.
>>> Please build qemu with --disable-strip and use 'perf' to profile it.
>> Done, I tried several different options, but I can't find
>> anything intesting in there.  Attaching a screenshot of
>> 3 - win7 guest (~5 minutes after startup), `perf top'
>> in xterm and `top' in another xterm.
>>
>> Here are random snapshots of both, in text form:
>>
>>  PerfTop:    1409 irqs/sec  kernel:79.6%  exact:  0.0% [1000Hz cycles],  (all, 2 CPUs)
>>
>>   samples  pcnt function               DSO
>>   _______ _____ __________________    _________________
>>  11837.00 64.9% native_safe_halt      [kernel.kallsyms]
>>    570.00  3.1% rb_next               [kernel.kallsyms]
>>    206.00  1.1% hpet_next_event       [kernel.kallsyms]
>>    149.00  0.8% do_select             [kernel.kallsyms]
>>    149.00  0.8% svm_vcpu_run          [kvm_amd]
>>    134.00  0.7% schedule              [kernel.kallsyms]
>>
>>
>> Tasks: 199 total,   2 running, 196 sleeping,   0 stopped,   1 zombie
>> Cpu(s): 13.4%us, 10.2%sy,  0.0%ni, 76.3%id,  0.0%wa,  0.0%hi, 0.2%si,  0.0%st
>> Mem:   5860724k total,  4601132k used,  1259592k free,    18508k buffers
>> Swap:  4192928k total,   286928k used,  3906000k free,  1593908k cached
>>
>>    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>> 28492 mjt       20   0 1111m 1.0g 5456 R   27 17.7   3:50.79 qemu-system-x86
>> 28763 root      20   0  105m  30m 6176 S   11  0.5 184:08.58 Xorg
>> 29263 mjt       20   0  637m 212m  11m S    6  3.7  92:08.82 firefox-bin
>> 28845 mjt       20   0 58612 5840 2372 S    2  0.1  49:27.17 compiz
>>
>> I'm still not sure where to look at.. :)
> 
> Strange.  Can you also post a few lines of 'vmstat 1'?
> 
> Maybe we'll see a lot of context switches in there.

Not that many.  Still running the same w7 guest, still
~25..27% CPU usage reported by top for the kvm process,
here's `vmstat 5' after a while (I tend to use larger
delay to mitigate large(ish) spikes):

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
0  0 286764 1262976  20640 1618468    0    0     0    24 6206 4460  7  9 84  0
1  0 286764 1263040  20640 1618436    0    0     0     0 6080 4415  7  9 84  0
1  0 286764 1264380  20648 1618448    0    0     0     5 6332 4576  8 11 81  0
1  0 286760 1264700  20656 1618436    6    0     6    18 6464 4742  7  8 84  1
1  0 286760 1264864  20664 1618472    0    0     0    10 6266 4704  8  8 85  0
0  0 286760 1265004  20668 1618440    0    0     0     1 6330 4683  6  8 86  0
0  0 286760 1264660  20668 1618452    0    0     0     1 6401 4675  7  8 85  0
1  0 286760 1264668  20668 1618464    0    0     0     0 6239 4688  7  8 85  0
0  0 286760 1264692  20676 1618472    0    0     0    10 6445 4703  7  9 84  0
1  0 286760 1264204  20676 1618480    0    0     8     1 6180 4587  7  8 85  1
0  0 286760 1263956  20684 1618492    0    0     0    10 6314 4630  7  9 83  0
0  0 286760 1263972  20684 1618504    0    0     0     0 6222 4569  7  9 84  0
2  0 286760 1264128  20692 1618504    0    0     0    18 6458 5006  8  9 83  0

Thanks!

/mjt