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From: Mathias Klette <mklette@gmail.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: Degraded performance with Windows 2008 R2 with applications
Date: Mon, 07 Mar 2011 19:10:41 +0100	[thread overview]
Message-ID: <4D751FA1.6020205@gmail.com> (raw)
In-Reply-To: <AANLkTi=FAePaXFtVotnfArNPCBpV0Y4zBOv93xdSERZC@mail.gmail.com>

On 07/03/11 10:41, Stefan Hajnoczi wrote:
> On Sun, Mar 6, 2011 at 10:25 PM, Mathias Klette<mklette@gmail.com>  wrote:
>> I've tested with iozone to compare IO with a linux guest and also to
>> verify changes made to improve situation - but nothing really helped.
>>
>> TESTS with "iozone -s 4G -r 256k -c -e":
>
> Please use the -I option to bypass the page cache, otherwise buffered
> I/O will be used and requests may be satisfied from memory rather than
> actually accessing the disk.
>
thanks, wasn't really aware of that switch.

here now tests, with a raw image on ext4 LV mounted with option 
relatime. vm has 4cores, 8G memory.
                                                             random 
random    bkwd   record   stride
               KB  reclen   write rewrite    read    reread    read 
write    read  rewrite     read   fwrite frewrite   fread  freread
          4194304     256  116922   43874   53701     34459   62807 
40152  152029  3519190   126013    38504    74360   24814    25112
          4194304     256  102275   48545   24342     33265   67412 
40945   59097  3500722   114174    73353    44401   46383    31860
          4194304     256   49306   45876   31610     31285  187091 
37275   59135  3472783    54016    65711    70700   24674    49231
          4194304     256   85590   90679   31319     47120  269864 
38727  137024  3462054    48674    73425    44879   46736    31684
          4194304     256   40474   27725   46137     46084  180579 
38938   57869  3473130    52202    36281    90943   31189    32703

unfortunately kvm_stat wasn't possible as debugfs is not compiled in.

vmstat 15 on host for the time of one iozone run:

procs -----------memory---------- ---swap-- -----io---- -system-- 
----cpu----
  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy 
id wa
  0  0      0 53722472 809620 160285216    0    0     2    17    1    0 
  0  1 98  0
  7  0      0 53726724 809648 160285280    0    0     0 24761 12731 
16822  1  1 98  0
  7  0      0 53722752 809672 160285296    0    0     0 120753 23707 
15666  1  2 97  0
  6  0      0 53724780 809688 160285344    0    0     0 86676 13572 
17537  1  1 98  0
  2  0      0 53725188 809716 160285392    0    0     1 72324 23238 
16397  0  2 98  0
  1  0      0 53728600 809740 160285424    0    0     0    24 10909 
13529  0  1 99  0
  0  0      0 53725612 809760 160285488    0    0     1    44 10469 
12467  0  1 99  0
  0  0      0 53726592 809784 160285680    0    0     1   299 11871 
15643  0  1 99  0
  1  0      0 53727512 809800 160285696    0    0     0    29 10635 
13284  0  1 99  0
  2  0      0 53727952 809832 160285776    0    0     1    53 10483 
12935  0  1 99  0
  1  0      0 53726348 809856 160285840    0    0     1    54 10384 
12600  0  1 99  0
  1  0      0 53727096 809880 160285856    0    0     0   108 10902 
13659  0  1 99  0
  1  0      0 53727328 809904 160285920    0    0     0    38 10348 
12692  0  1 99  0
  0  0      0 53728328 809928 160285952    0    0     0    33 10137 
12195  0  1 99  0
  1  0      0 53727680 809952 160286000    0    0     0    35 10653 
13327  0  1 99  0
  1  0      0 53727616 809968 160286112    0    0     0    31 10465 
12932  0  0 99  0
  0  0      0 53728148 809992 160286128    0    0     0    17 10037 
11946  0  0 99  0
  0  0      0 53727756 810016 160286192    0    0     1    29 13424 
18647  1  1 98  0
  5  0      0 53711500 810040 160286224    0    0     0    41 16580 
24443  1  2 97  0
  3  0      0 53724776 810076 160286288    0    0     1    61 13441 
18676  1  1 98  0
  0  0      0 53721816 810108 160286320    0    0     0 201432 14520 
14391  0  2 97  1
  6  0      0 53724704 810128 160286368    0    0     0    36 11088 
14476  0  1 99  0
  0  0      0 53725068 810164 160286432    0    0     0 78247 11450 
12167  1  2 97  1
  7  0      0 53626104 810188 160382512    0    0     0    35 11459 
14319  1  1 98  0
  3  0      0 53605924 810208 160402400    0    0     0    18 12609 
15837  2  1 97  0
  2  0      0 53589232 810356 160416864    0    0     0  8471 12203 
14956  2  1 97  0
  3  0      0 53570564 810372 160434128    0    0     0    26 11359 
13451  2  1 97  0
  0  0      0 53569516 810428 160438400    0    0     0  1735 10793 
12836  2  1 98  0
  1  0      0 53570652 810452 160438432    0    0     0    24 10816 
13483  0  1 99  0
  1  0      0 53570472 810476 160438496    0    0     0    61 11613 
14829  0  1 99  0
  5  0      0 53567268 810500 160438512    0    0     0    22 12978 
17810  1  1 98  0
  8  0      0 53564892 810528 160438816    0    0     0 150075 25535 
23496  0  2 98  0
  6  0      0 53565608 810552 160438848    0    0     0 27318 13518 
16144  0  1 99  0
  4  0      0 53566828 810576 160438912    0    0     0 102318 13783 
15730  1  1 98  0
  1  0      0 53564064 810600 160438944    0    0     0 84140 18573 
20191  1  2 98  0
  3  0      0 53564344 810616 160438992    0    0     0 131089 21789 
21013  0  2 98  0
  6  0      0 53565948 810640 160439008    0    0     0 17110 12010 
11942  0  1 99  0
  1  0      0 53567380 810656 160439056    0    0     0 47398 18252 
13303  0  1 99  0
  1  0      0 53550740 810684 160439104    0    0     0    25 10505 
12964  0  1 99  0
  2  0      0 53564948 810716 160439216    0    0     1    60 10113 
12037  0  1 99  0
  2  0      0 53566988 810740 160439264    0    0     0    39 10720 
13451  0  1 99  0
  1  0      0 53566420 810772 160439296    0    0     0    30 10526 
13053  0  1 99  0

regards top, i'm afraid to attach a log for the whole time iozone is 
being run. only remarkable: once iozone starts writing the kvm process 
requests more cpu time and ksoftirqd/18 and flush-253:1 show up for 
short times in the top 5 of the list.

> What is the qemu-kvm command-line (ps aux | grep kvm)?

106      14527 28.5  1.5 4413272 4223720 ?     Sl   15:04  58:50 
/usr/bin/kvm -S -M pc-0.13 -enable-kvm -m 4096 -smp 
4,sockets=4,cores=1,threads=1 -name Profitbricks-Linuxtest -uuid 
e4594cb9-6958-d564-8ed0-74ba828b9326 -nodefconfig -nodefaults -chardev 
socket,id=monitor,path=/var/lib/libvirt/qemu/VM-34.monitor,server,nowait 
-mon chardev=monitor,mode=readline -rtc base=localtime -boot dc -drive 
file=/images/VM-34.raw,if=none,id=drive-virtio-disk0,boot=on,format=raw,cache=writeback 
-device 
virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0 
-drive 
file=/images/virtio-win-1.1.16.iso,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw 
-device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 
-netdev tap,fd=90,id=hostnet0 -device 
e1000,netdev=hostnet0,id=net0,mac=52:54:00:4e:3c:6d,bus=pci.0,addr=0x3 
-netdev tap,fd=95,id=hostnet1 -device 
virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:37:4f:5f,bus=pci.0,addr=0x6 
-chardev pty,id=serial0 -device isa-serial,chardev=serial0 -usb -device 
usb-tablet,id=input0 -vnc 0.0.0.0:10 -k de -vga std -device 
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4

>
> Are you using virtio-blk and the Windows guest drivers from here:
>
> http://www.linux-kvm.org/page/WindowsGuestDrivers/Download_Drivers
yes, versions 1.1.16. as far as I've seen, there were no newer ones 
available?!
>
> Stefan

I checked with linux-2.6.38-rc6 with AMD IOMMU support today and got far 
better results and also it felt like a usable system:

                                                             random 
random    bkwd   record   stride
               KB  reclen   write rewrite    read    reread    read 
write    read  rewrite     read   fwrite frewrite   fread  freread
           4194304     256   64937  101079  245510    229593  265388 
79120  321497  3608593   273455    48558    99760  224877   224175
          4194304     256   49674   95625   66813    213311   70686 
79345  322612  3198246   272728    96646    99040  212715   210044
          4194304     256   97412   49211  204895    654454  246541 
75667   74149  3250535   260699    48806    99973  225283   225453


  reply	other threads:[~2011-03-07 18:10 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-06 22:25 Degraded performance with Windows 2008 R2 with applications Mathias Klette
2011-03-07  9:41 ` Stefan Hajnoczi
2011-03-07 18:10   ` Mathias Klette [this message]
2011-03-07  9:57 ` Avi Kivity

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