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<p class=MsoNormal><span lang=EN-US>Whe guest is running only a dd, the cpu utilization
of qemu-kvm reaches about 100%.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Host:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>top - 23:37:21 up 1 day, 2:07,
3 users, load average: 0.51, 0.97, 1.28<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Tasks: 427 total, 1 running,
426 sleeping, 0 stopped, 0 zombie<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Cpu(s): 2.2%us, 3.7%sy,
0.0%ni, 92.6%id, 1.5%wa, 0.0%hi, 0.0%si, 0.0%st<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Mem: 49552496k total, 24983432k used,
24569064k free, 19330008k buffers<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Swap: 8388600k
total, 0k used, 8388600k
free, 1187116k cached<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US> PID
USER PR NI VIRT RES SHR S
%CPU %MEM TIME+
COMMAND
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> 5606
qemu 40 0 9033m 2.5g 2972 S
106.0 5.4 3:36.34
qemu-kvm <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Guest:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>]# dd if=/dev/vda of=/dev/null bs=32k
iflag=direct<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>89155+0 records in<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>89154+0 records out<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>2921398272 bytes (2.9 GB) copied, 11.6572
seconds, 251 MB/s<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>top - 23:41:08 up 9 min, 2
users, load average: 0.38, 0.28, 0.15<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Tasks: 168 total, 1 running,
167 sleeping, 0 stopped, 0 zombie<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Cpu(s): 0.1%us, 6.3%sy,
0.0%ni, 86.9%id, 3.6%wa, 3.2%hi, 0.0%si, 0.0%st<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Mem: 4270192k
total, 91640k used, 4178552k
free, 2872k buffers<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Swap: 1048568k
total, 0k used, 1048568k
free, 14840k cached<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US> PID USER
PR NI VIRT RES SHR S %CPU %MEM
TIME+
COMMAND
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> 2935
root 18 0 63152 652 532 D
54.6 0.0 0:10.69
dd
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Meanwhile, do the same dd at host, cpu utilization
is less.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>]# dd if=/dev/vgxpool/kirby-dev-data0
of=/dev/null bs=32k iflag=direct <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>328541+0 records in<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>328540+0 records out<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>10765598720 bytes (11 GB) copied, 70.0218
s, 154 MB/s<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>top - 23:43:49 up 1 day, 2:14,
3 users, load average: 0.48, 0.44, 0.90<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Tasks: 426 total, 1 running,
425 sleeping, 0 stopped, 0 zombie<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Cpu(s): 0.0%us, 0.5%sy,
0.0%ni, 93.8%id, 5.4%wa, 0.0%hi, 0.2%si, 0.0%st<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Mem: 49552496k total, 14078580k used,
35473916k free, 11362396k buffers<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Swap: 8388600k
total, 0k used, 8388600k
free, 1187116k cached<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US> PID
USER PR NI VIRT RES SHR S
%CPU %MEM TIME+
COMMAND
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> 5873
root 40 0 101m 708
580 D 8.6 0.0 0:01.21
dd
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US> Regards<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> Kirby Zhou<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
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