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Poor performance with KVM, how to figure out why?

DISCUSSION Vegard Svanberg 3 participants 3 messages Feb 18, 2010 KVM

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#0 lore raw

Hi, sorry about the lengthy e-mail.

We've been evaluating KVM for a while. Currently the host is on 2.6.30-bpo.1-amd64, 4 CPU cores on an Intel Xeon 2,33. Disk controller is Areca ARC-1210 and the machine has 12GB of memory. KVM 85+dfsg-4~bpo50+1 and libvirt 0.6.5-3~bpo50+1, both from backports.org. Guests are in qcow2 images.

A few test servers have been running here for a while. That worked ok, so we've moved a few production servers on it as well. It's now running 8 guests, none of them are CPU or disk intensive (well, there are a mail server and web server there, which from time to time spike, but it's generally very low).

After a reboot the other day, performance is suddenly disaster. The only change we can see we've done is that we've allocated a bit more memory to the guests, and enabled 4 vcpus on all guests (some of them ran with 1 vcpu before). When I say performance is bad, it's to the point where typing on the keyboard is lagging. It seems load on one guest affects all of the others.

What is weird is that before the reboot, the host machine usually had a system load of about 0.30 on average, and a CPU load of 20-30% (total of all cores). After the reboot, this is a typical top output:

top - 11:17:49 up 1 day, 5:32, 3 users, load average: 3.81, 3.85, 3.96

Tasks: 113 total,   4 running, 109 sleeping,   0 stopped,   0 zombie
Cpu0  : 93.7%us,  3.6%sy,  0.0%ni,  0.7%id,  1.7%wa,  0.3%hi,  0.0%si,  0.0%st
Cpu1  : 96.3%us,  3.7%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  : 93.7%us,  5.0%sy,  0.0%ni,  1.0%id,  0.0%wa,  0.0%hi,  0.3%si,  0.0%st
Cpu3  : 91.4%us,  5.6%sy,  0.0%ni,  2.7%id,  0.0%wa,  0.0%hi,  0.3%si,  0.0%st
Mem:  12335492k total, 12257056k used,    78436k free,       24k buffers
Swap:  7807580k total,   744584k used,  7062996k free,  4927212k cached
  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 3398 root      20   0 2287m 1.9g  680 S  149 16.5 603:10.92 kvm
 5041 root      20   0 2255m 890m  540 R   99  7.4 603:38.07 kvm
 5055 root      20   0 2272m 980m  668 S   86  8.1 305:42.95 kvm
 5095 root      20   0 2287m 1.9g  532 R   33 16.6 655:11.53 kvm
 5073 root      20   0 2253m 435m  532 S   19  3.6 371:59.80 kvm
 3334 root      20   0 2254m  66m  532 S    6  0.5 106:58.20 kvm

Now this is the weird part: The guests are (really!) doing nothing. Before this started, each guest's load were typically 0.02 - 0.30. Now their load is suddenly 2.x and in top, even simple CPU processes like syslogd uses 20% CPU.

It _might_ seem like an i/o problem, because disk performance seems bad on all guests. find / would ususally fly by, now you'd see a bit lag'ish output (I know, bad performance test).

The host machine seems fast&fine, except it has a system load of about 2-6. It seems snappy, though. Here you have some info like iostat etc:

# iostat -kdxx1 

inux 2.6.30-bpo.1-amd64 (cf01) 02/18/2010 _x86_64_

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
sda               1.73    18.91   29.89   18.40   855.89   454.17    54.26     0.48    9.98   2.23  10.75
sda1              0.35    16.17   29.58   18.24   849.11   442.58    54.03     0.47    9.79   2.20  10.52

sda2 1.38 2.74 0.31 0.16 6.78 11.59 77.44 0.01 29.14 13.60 0.64

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util

sda               6.00     0.00    1.00    0.00     4.00     0.00     8.00     0.31    0.00 308.00  30.80
sda1              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
sda2              6.00     0.00    1.00    0.00     4.00     0.00     8.00     0.31    0.00 308.00  30.80
Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
sda               0.00     0.00    1.00    0.00    28.00     0.00    56.00     0.63  936.00 628.00  62.80
sda1              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
sda2              0.00     0.00    1.00    0.00    28.00     0.00    56.00     0.63  936.00 628.00  62.80

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util

sda               0.00     0.00    4.00    0.00   228.00     0.00   114.00     0.04    9.00   5.00   2.00
sda1              0.00     0.00    4.00    0.00   228.00     0.00   114.00     0.04    9.00   5.00   2.00
sda2              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
sda               6.00     0.00    3.00    0.00    36.00     0.00    24.00     0.06   21.33  14.67   4.40
sda1              0.00     0.00    1.00    0.00     4.00     0.00     8.00     0.02   24.00  24.00   2.40
sda2              6.00     0.00    2.00    0.00    32.00     0.00    32.00     0.04   20.00  10.00   2.00

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util

sda               4.00     0.00    2.00   92.00    24.00   786.50    17.24     0.03    0.34   0.17   1.60
sda1              0.00     0.00    0.00   92.00     0.00   786.50    17.10     0.00    0.00   0.00   0.00
sda2              4.00     0.00    2.00    0.00    24.00     0.00    24.00     0.03   16.00   8.00   1.60

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util

sda               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
sda1              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
sda2              0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
# vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 4  0 747292  98584     24 4912368    2    3   207   110    8   14 35  5 58  2
# vmstat -d
disk- ------------reads------------ ------------writes----------- -----IO------
       total merged sectors      ms  total merged sectors      ms    cur    sec
ram0       0      0       0       0      0      0       0       0      0      0
ram1       0      0       0       0      0      0       0       0      0      0
ram2       0      0       0       0      0      0       0       0      0      0
ram3       0      0       0       0      0      0       0       0      0      0
ram4       0      0       0       0      0      0       0       0      0      0
ram5       0      0       0       0      0      0       0       0      0      0
ram6       0      0       0       0      0      0       0       0      0      0
ram7       0      0       0       0      0      0       0       0      0      0
ram8       0      0       0       0      0      0       0       0      0      0
ram9       0      0       0       0      0      0       0       0      0      0
ram10      0      0       0       0      0      0       0       0      0      0
ram11      0      0       0       0      0      0       0       0      0      0
ram12      0      0       0       0      0      0       0       0      0      0
ram13      0      0       0       0      0      0       0       0      0      0
ram14      0      0       0       0      0      0       0       0      0      0
ram15      0      0       0       0      0      0       0       0      0      0
sda   3170691 184220 181548275 19898284 1952716 2005771 96380008 31234880      0  11405
sda1  3137240  37285 180105335 18834360 1935681 1715307 93920016 30830644      0  11162
sda2   33429 146912 1442580 1063828  17035 290464 2459992  404236      0    685
sr0        0      0       0       0      0      0       0       0      0      0
loop0      0      0       0       0      0      0       0       0      0      0
loop1      0      0       0       0      0      0       0       0      0      0
loop2      0      0       0       0      0      0       0       0      0      0
loop3      0      0       0       0      0      0       0       0      0      0
loop4      0      0       0       0      0      0       0       0      0      0
loop5      0      0       0       0      0      0       0       0      0      0
loop6      0      0       0       0      0      0       0       0      0      0
loop7      0      0       0       0      0      0       0       0      0      0
# kvmstat

kvm statistics

efer_reload 2493 0
exits 7012998022 86420
fpu_reload 107956245 1121
halt_exits 839269827 10930
halt_wakeup 79528805 1364

 host_state_reload   1159155068   15293
 hypercalls          1471039754   17008
 insn_emulation      2782749902   35121
 insn_emulation_fail          0       0
 invlpg               172119687    1754
 io_exits             129482688    2084
 irq_exits            455515434    4884
 irq_injections       973172925   12423
 irq_window            41631517     635
 largepages                   0       0
 mmio_exits              941756       0
 mmu_cache_miss        74512394     849
 mmu_flooded            5132926      41
 mmu_pde_zapped        40341877     356
 mmu_pte_updated     1150029759   13443
 mmu_pte_write       2184765599   27182
 mmu_recycled             52261       0
 mmu_shadow_zapped     74494953     766
 mmu_unsync                 390      23
 mmu_unsync_global            0       0
 nmi_injections               0       0
 nmi_window                   0       0
 pf_fixed             470057939    5144
 pf_guest             463801876    5900
 remote_tlb_flush     128765057    1024
 request_irq                  0       0
 request_nmi                  0       0
 signal_exits                 0       0

tlb_flush 1528830191 17996

Any hints on how to figure out why this happens? Thanks!

Signature · 1 line
Vegard Svanberg <[email protected]> [*Takapa@IRC (EFnet)]
#1 lore raw
Quoted 7 lines · Vegard Svanberg

Hi, sorry about the lengthy e-mail.

We've been evaluating KVM for a while. Currently the host is on 2.6.30-bpo.1-amd64, 4 CPU cores on an Intel Xeon 2,33. Disk controller is Areca ARC-1210 and the machine has 12GB of memory. KVM 85+dfsg-4~bpo50+1 and libvirt 0.6.5-3~bpo50+1, both from backports.org. Guests are in qcow2 images.

These are all really old.

Quoted 17 lines

A few test servers have been running here for a while. That worked ok, so we've moved a few production servers on it as well. It's now running 8 guests, none of them are CPU or disk intensive (well, there are a mail server and web server there, which from time to time spike, but it's generally very low).

After a reboot the other day, performance is suddenly disaster. The only change we can see we've done is that we've allocated a bit more memory to the guests, and enabled 4 vcpus on all guests (some of them ran with 1 vcpu before). When I say performance is bad, it's to the point where typing on the keyboard is lagging. It seems load on one guest affects all of the others.

What is weird is that before the reboot, the host machine usually had a system load of about 0.30 on average, and a CPU load of 20-30% (total of all cores). After the reboot, this is a typical top output:

Quoted 9 lines

top - 11:17:49 up 1 day, 5:32, 3 users, load average: 3.81, 3.85, 3.96

Tasks: 113 total,   4 running, 109 sleeping,   0 stopped,   0 zombie
Cpu0  : 93.7%us,  3.6%sy,  0.0%ni,  0.7%id,  1.7%wa,  0.3%hi,  0.0%si,  0.0%st
Cpu1  : 96.3%us,  3.7%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  : 93.7%us,  5.0%sy,  0.0%ni,  1.0%id,  0.0%wa,  0.0%hi,  0.3%si,  0.0%st
Cpu3  : 91.4%us,  5.6%sy,  0.0%ni,  2.7%id,  0.0%wa,  0.0%hi,  0.3%si,  0.0%st
Mem:  12335492k total, 12257056k used,    78436k free,       24k buffers
Swap:  7807580k total,   744584k used,  7062996k free,  4927212k cached

Looks like you're running into swap. Does 'vmstat 1' show swap activity?

Try dropping the vcpu count and memory back to initial levels, separately, to see which triggers the bad behaviour.

Quoted 8 lines
   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  3398 root      20   0 2287m 1.9g  680 S  149 16.5 603:10.92 kvm
  5041 root      20   0 2255m 890m  540 R   99  7.4 603:38.07 kvm
  5055 root      20   0 2272m 980m  668 S   86  8.1 305:42.95 kvm
  5095 root      20   0 2287m 1.9g  532 R   33 16.6 655:11.53 kvm
  5073 root      20   0 2253m 435m  532 S   19  3.6 371:59.80 kvm
  3334 root      20   0 2254m  66m  532 S    6  0.5 106:58.20 kvm

None of the RSS figures are nice round numbers, which might mean some of guest memory is swapped out.

(note: you can run kvm as non-root).

Quoted 5 lines

Now this is the weird part: The guests are (really!) doing nothing. Before this started, each guest's load were typically 0.02 - 0.30. Now their load is suddenly 2.x and in top, even simple CPU processes like syslogd uses 20% CPU.

That may also be an indication of swap. When the guest accesses a swapped out page, the time to swap in the page is accounted to the instruction that caused the access.

Quoted 5 lines
# vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
  4  0 747292  98584     24 4912368    2    3   207   110    8   14 35  5 58  2

'vmstat' rate data is from machine boot up. 'vmstat 1' gives current rates.

Quoted 35 lines

kvm statistics

efer_reload 2493 0
exits 7012998022 86420
fpu_reload 107956245 1121
halt_exits 839269827 10930
halt_wakeup 79528805 1364

  host_state_reload   1159155068   15293
  hypercalls          1471039754   17008
  insn_emulation      2782749902   35121
  insn_emulation_fail          0       0
  invlpg               172119687    1754
  io_exits             129482688    2084
  irq_exits            455515434    4884
  irq_injections       973172925   12423
  irq_window            41631517     635
  largepages                   0       0
  mmio_exits              941756       0
  mmu_cache_miss        74512394     849
  mmu_flooded            5132926      41
  mmu_pde_zapped        40341877     356
  mmu_pte_updated     1150029759   13443
  mmu_pte_write       2184765599   27182
  mmu_recycled             52261       0
  mmu_shadow_zapped     74494953     766
  mmu_unsync                 390      23
  mmu_unsync_global            0       0
  nmi_injections               0       0
  nmi_window                   0       0
  pf_fixed             470057939    5144
  pf_guest             463801876    5900
  remote_tlb_flush     128765057    1024
  request_irq                  0       0
  request_nmi                  0       0
  signal_exits                 0       0
Quoted 3 lines

tlb_flush 1528830191 17996

This is reasonable for a 4-cpu host under moderate load.

Signature · 1 line
error compiling committee.c: too many arguments to function
#2 lore raw
In reply to Vegard Svanberg
Quoted 1 line · On Thursday 18 February 2010 11:31:36 you wrote:

Hi, sorry about the lengthy e-mail.

Hi,

are you sure the kvm-intel kernel module is loaded?

What is the output of "lsmod" ?

Any useful kernel messages on the host or the VMs? What's the output of "dmesg"?

Cheers,

Thomas

Quoted 185 lines

We've been evaluating KVM for a while. Currently the host is on 2.6.30-bpo.1-amd64, 4 CPU cores on an Intel Xeon 2,33. Disk controller is Areca ARC-1210 and the machine has 12GB of memory. KVM 85+dfsg-4~bpo50+1 and libvirt 0.6.5-3~bpo50+1, both from backports.org. Guests are in qcow2 images.

A few test servers have been running here for a while. That worked ok, so we've moved a few production servers on it as well. It's now running 8 guests, none of them are CPU or disk intensive (well, there are a mail server and web server there, which from time to time spike, but it's generally very low).

After a reboot the other day, performance is suddenly disaster. The only change we can see we've done is that we've allocated a bit more memory to the guests, and enabled 4 vcpus on all guests (some of them ran with 1 vcpu before). When I say performance is bad, it's to the point where typing on the keyboard is lagging. It seems load on one guest affects all of the others.

What is weird is that before the reboot, the host machine usually had a system load of about 0.30 on average, and a CPU load of 20-30% (total of all cores). After the reboot, this is a typical top output:

top - 11:17:49 up 1 day, 5:32, 3 users, load average: 3.81, 3.85, 3.96
Tasks: 113 total, 4 running, 109 sleeping, 0 stopped, 0 zombie
Cpu0 : 93.7%us, 3.6%sy, 0.0%ni, 0.7%id, 1.7%wa, 0.3%hi, 0.0%si,

0.0%st Cpu1  : 96.3%us,  3.7%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi, 
0.0%si,  0.0%st Cpu2  : 93.7%us,  5.0%sy,  0.0%ni,  1.0%id,  0.0%wa, 
0.0%hi,  0.3%si,  0.0%st Cpu3  : 91.4%us,  5.6%sy,  0.0%ni,  2.7%id, 

0.0%wa, 0.0%hi, 0.3%si, 0.0%st Mem: 12335492k total, 12257056k used,
78436k free, 24k buffers Swap: 7807580k total, 744584k used,
7062996k free, 4927212k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 3398 root      20   0 2287m 1.9g  680 S  149 16.5 603:10.92 kvm
 5041 root      20   0 2255m 890m  540 R   99  7.4 603:38.07 kvm
 5055 root      20   0 2272m 980m  668 S   86  8.1 305:42.95 kvm
 5095 root      20   0 2287m 1.9g  532 R   33 16.6 655:11.53 kvm
 5073 root      20   0 2253m 435m  532 S   19  3.6 371:59.80 kvm
 3334 root      20   0 2254m  66m  532 S    6  0.5 106:58.20 kvm

Now this is the weird part: The guests are (really!) doing nothing. Before this started, each guest's load were typically 0.02 - 0.30. Now their load is suddenly 2.x and in top, even simple CPU processes like syslogd uses 20% CPU.

It _might_ seem like an i/o problem, because disk performance seems bad on all guests. find / would ususally fly by, now you'd see a bit lag'ish output (I know, bad performance test).

The host machine seems fast&fine, except it has a system load of about 2-6. It seems snappy, though. Here you have some info like iostat etc:

# iostat -kdxx1

inux 2.6.30-bpo.1-amd64 (cf01) 02/18/2010 _x86_64_

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
avgqu-sz await svctm %util sda 1.73 18.91 29.89
18.40 855.89 454.17 54.26 0.48 9.98 2.23 10.75 sda1

       0.35    16.17   29.58   18.24   849.11   442.58    54.03     0.47  

9.79 2.20 10.52 sda2 1.38 2.74 0.31 0.16
6.78 11.59 77.44 0.01 29.14 13.60 0.64

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
avgqu-sz await svctm %util sda 6.00 0.00 1.00
0.00 4.00 0.00 8.00 0.31 0.00 308.00 30.80 sda1

      0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00   

0.00 0.00 0.00 sda2 6.00 0.00 1.00 0.00
4.00 0.00 8.00 0.31 0.00 308.00 30.80

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
avgqu-sz await svctm %util sda 0.00 0.00 1.00
0.00 28.00 0.00 56.00 0.63 936.00 628.00 62.80 sda1

      0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00   

0.00 0.00 0.00 sda2 0.00 0.00 1.00 0.00
28.00 0.00 56.00 0.63 936.00 628.00 62.80

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await  svctm  %util sda               0.00     0.00    4.00   
0.00   228.00     0.00   114.00     0.04    9.00   5.00   2.00 sda1       
      0.00     0.00    4.00    0.00   228.00     0.00   114.00     0.04   

9.00 5.00 2.00 sda2 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz

avgqu-sz   await  svctm  %util sda               6.00     0.00    3.00   
0.00    36.00     0.00    24.00     0.06   21.33  14.67   4.40 sda1       
      0.00     0.00    1.00    0.00     4.00     0.00     8.00     0.02  

24.00 24.00 2.40 sda2 6.00 0.00 2.00 0.00
32.00 0.00 32.00 0.04 20.00 10.00 2.00

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz
avgqu-sz await svctm %util sda 4.00 0.00 2.00
92.00 24.00 786.50 17.24 0.03 0.34 0.17 1.60 sda1

       0.00     0.00    0.00   92.00     0.00   786.50    17.10     0.00  

0.00 0.00 0.00 sda2 4.00 0.00 2.00 0.00
24.00 0.00 24.00 0.03 16.00 8.00 1.60

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz

avgqu-sz   await  svctm  %util sda               0.00     0.00    0.00   
0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00 sda1       
      0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00   

0.00 0.00 0.00 sda2 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00

# vmstat
procs -----------memory---------- ---swap-- -----io---- -system--
----cpu---- r  b   swpd   free   buff  cache   si   so    bi    bo   in  
cs us sy id wa 4  0 747292  98584     24 4912368    2    3   207   110   
8   14 35  5 58  2 # vmstat -d
disk- ------------reads------------ ------------writes-----------
-----IO------ total merged sectors      ms  total merged sectors      ms  
 cur    sec ram0       0      0       0       0      0      0       0     
 0      0      0 ram1       0      0       0       0      0      0       0
      0      0      0 ram2       0      0       0       0      0      0   
   0       0      0      0 ram3       0      0       0       0      0     
0       0       0      0      0 ram4       0      0       0       0      0
     0       0       0      0      0 ram5       0      0       0       0  
   0      0       0       0      0      0 ram6       0      0       0     
 0      0      0       0       0      0      0 ram7       0      0       0
      0      0      0       0       0      0      0 ram8       0      0   
   0       0      0      0       0       0      0      0 ram9       0     
0       0       0      0      0       0       0      0      0 ram10      0
     0       0       0      0      0       0       0      0      0 ram11  
   0      0       0       0      0      0       0       0      0      0
ram12      0      0       0       0      0      0       0       0      0  
   0 ram13      0      0       0       0      0      0       0       0    
 0      0 ram14      0      0       0       0      0      0       0      
0      0      0 ram15      0      0       0       0      0      0       0 
     0      0      0 sda   3170691 184220 181548275 19898284 1952716
2005771 96380008 31234880      0  11405 sda1  3137240  37285 180105335
18834360 1935681 1715307 93920016 30830644      0  11162 sda2   33429
146912 1442580 1063828  17035 290464 2459992  404236      0    685 sr0    
   0      0       0       0      0      0       0       0      0      0
loop0      0      0       0       0      0      0       0       0      0  
   0 loop1      0      0       0       0      0      0       0       0    
 0      0 loop2      0      0       0       0      0      0       0      
0      0      0 loop3      0      0       0       0      0      0       0 
     0      0      0 loop4      0      0       0       0      0      0    
  0       0      0      0 loop5      0      0       0       0      0     
0       0       0      0      0 loop6      0      0       0       0      0
     0       0       0      0      0 loop7      0      0       0       0  
   0      0       0       0      0      0
# kvmstat

kvm statistics

efer_reload 2493 0
exits 7012998022 86420
fpu_reload 107956245 1121
halt_exits 839269827 10930
halt_wakeup 79528805 1364

 host_state_reload   1159155068   15293
 hypercalls          1471039754   17008
 insn_emulation      2782749902   35121
 insn_emulation_fail          0       0
 invlpg               172119687    1754
 io_exits             129482688    2084
 irq_exits            455515434    4884
 irq_injections       973172925   12423
 irq_window            41631517     635
 largepages                   0       0
 mmio_exits              941756       0
 mmu_cache_miss        74512394     849
 mmu_flooded            5132926      41
 mmu_pde_zapped        40341877     356
 mmu_pte_updated     1150029759   13443
 mmu_pte_write       2184765599   27182
 mmu_recycled             52261       0
 mmu_shadow_zapped     74494953     766
 mmu_unsync                 390      23
 mmu_unsync_global            0       0
 nmi_injections               0       0
 nmi_window                   0       0
 pf_fixed             470057939    5144
 pf_guest             463801876    5900
 remote_tlb_flush     128765057    1024
 request_irq                  0       0
 request_nmi                  0       0
 signal_exits                 0       0

tlb_flush 1528830191 17996

Any hints on how to figure out why this happens? Thanks!