Debian Bug report logs - #574988
cirrus emulation is slow for some guests in 0.12

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Adam Majer <adamm@zombino.com>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: Video access much slower than kvm-72 or any "snapshot" versions

Date: Mon, 22 Mar 2010 12:44:46 -0500

Package: qemu-kvm
Version: 0.12.3+dfsg-4
Severity: normal

I've been using KVM for quite some time now to run Windows XP, 2000,
Vista, and Win 7. Though all the generations of KVM, video speed was
acceptable. After installing qemu-kvm, video display speed inside the
VM has slowed down to below acceptable level. As an example,

1. run XP
2. go to command line
3. type dir
4. repeat #3 until window scrolls

Once the output is scrolling, the speed of redraw has slowed down from
about 1-2s per page (in the kvm-xxx flavours of the package) to
0.5s/line (in the 0.xx flavours of the package). This is about 10x slower.


- Adam


-- Package-specific info:


/proc/cpuinfo:

processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 15
model		: 75
model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
stepping	: 2
cpu MHz		: 1000.000
cache size	: 512 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 2
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
bogomips	: 2008.96
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts fid vid ttp tm stc

processor	: 1
vendor_id	: AuthenticAMD
cpu family	: 15
model		: 75
model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
stepping	: 2
cpu MHz		: 1000.000
cache size	: 512 KB
physical id	: 0
siblings	: 2
core id		: 1
cpu cores	: 2
apicid		: 1
initial apicid	: 1
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
bogomips	: 2008.96
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts fid vid ttp tm stc




-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (50, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.33-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_CA.UTF-8, LC_CTYPE=en_CA.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages qemu-kvm depends on:
ii  adduser                 3.112            add and remove users and groups
ii  bridge-utils            1.4-5            Utilities for configuring the Linu
ii  iproute                 20100224-3       networking and traffic control too
ii  libaio1                 0.3.107-7        Linux kernel AIO access library - 
ii  libasound2              1.0.22-2         shared library for ALSA applicatio
ii  libbluetooth3           4.60-1           Library to use the BlueZ Linux Blu
ii  libbrlapi0.5            4.1-4            braille display access via BRLTTY 
ii  libc6                   2.10.2-6         Embedded GNU C Library: Shared lib
ii  libcurl3-gnutls         7.20.0-1         Multi-protocol file transfer libra
ii  libgnutls26             2.8.5-2          the GNU TLS library - runtime libr
ii  libncurses5             5.7+20100313-1   shared libraries for terminal hand
ii  libpci3                 1:3.1.7-2        Linux PCI Utilities (shared librar
ii  libpulse0               0.9.21-1         PulseAudio client libraries
ii  libsasl2-2              2.1.23.dfsg1-5   Cyrus SASL - authentication abstra
ii  libsdl1.2debian         1.2.14-4         Simple DirectMedia Layer
ii  libuuid1                2.16.2-0         Universally Unique ID library
ii  libvdeplug2             2.2.3-3          Virtual Distributed Ethernet - Plu
ii  libx11-6                2:1.3.3-2        X11 client-side library
ii  python                  2.5.4-9          An interactive high-level object-o
ii  zlib1g                  1:1.2.3.4.dfsg-3 compression library - runtime

Versions of packages qemu-kvm recommends:
ii  linux-image-2.6. 2.6.26-21               Linux 2.6.26 image on AMD64
ii  linux-image-2.6. 2.6.32-6                Linux 2.6.32 for 64-bit PCs
ii  linux-image-2.6. 2.6.32-10               Linux 2.6.32 for 64-bit PCs
ii  linux-image-2.6. 2.6.33-1~experimental.2 Linux 2.6.33 for 64-bit PCs

Versions of packages qemu-kvm suggests:
ii  debootstrap                   1.0.22     Bootstrap a basic Debian system
pn  samba                         <none>     (no description available)
pn  vde2                          <none>     (no description available)

-- no debconf information

Message #10 received at 574988@bugs.debian.org (full text, mbox, reply):

From: Michael Tokarev <mjt@tls.msk.ru>

To: Adam Majer <adamm@zombino.com>, 574988@bugs.debian.org

Subject: Re: Bug#574988: Video access much slower than kvm-72 or any "snapshot" versions

Date: Mon, 22 Mar 2010 21:06:47 +0300

tags 574988 + moreinfo
thanks

Adam Majer wrote:
> Package: qemu-kvm
> Version: 0.12.3+dfsg-4
> Severity: normal
> 
> I've been using KVM for quite some time now to run Windows XP, 2000,
> Vista, and Win 7. Though all the generations of KVM, video speed was
> acceptable. After installing qemu-kvm, video display speed inside the
> VM has slowed down to below acceptable level. As an example,
> 
> 1. run XP
> 2. go to command line
> 3. type dir
> 4. repeat #3 until window scrolls
> 
> Once the output is scrolling, the speed of redraw has slowed down from
> about 1-2s per page (in the kvm-xxx flavours of the package) to
> 0.5s/line (in the 0.xx flavours of the package). This is about 10x slower.

I just tried it with 0.12.3+dfsg-4 (the one that entered -testing today).
I see almost instant scrolling in winXP and w2k3 cmd window.  `dir' in
C:\Windows directory takes a few fractions of a second to scroll.  I even
tried resizing window to full desktop size and changing font to smaller
one so that more lines fits in the window (I mean the cmd window inside
the guest) - it is still fast, at least I see no visible slowdown compared
with native windows.  Not even remotely like 1-2s per page or even not
0.5s per PAGE.

I tried both -vga std and -vga cirrus (the latter is the default) - to same
extent.

I can partially confirm that when host and guest _color_ depth does not
match (e.g. 16bit color in guest when in host it's 24bit), the mentioned
scrolling slows down quite a bit, and becomes at least comparable to 0.5s
per PAGE (again, not per LINE).  Maybe this is the issue you have?

> processor	: 0
> vendor_id	: AuthenticAMD
> cpu family	: 15
> model		: 75
> model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+

One thing I notice is that my CPU is quite a bit faster than this:
mine is running at 2.5GHz.  So that may explain the difference between
your 1-2s/page with my less than 0.5s/page, in case of bad matching of
color depth, but the difference is still larger than I'd expect based
solely on cpu speed (mine is of the same generation, Athlon x2 64).

Note also that since probably kvm-0.11 (kvm-85) the guest window
become resizable, and kvm scales the guest image to match the window
size.  This too requires some processing.  In order to be sure there's
1:1 ratio between guest and window size, switch to full-screen mode and
back (Hit Ctrl+Alt+F two times).

And also, you didn't mention which way you use to see the guest.
If you're using sdl window it's one thing, when using vnc console
it's entirely different thing.

So I'm tagging this as "moreinfo" for now.

Thanks!

/mjt

Message #17 received at 574988@bugs.debian.org (full text, mbox, reply):

From: Adam Majer <adamm@zombino.com>

To: Michael Tokarev <mjt@tls.msk.ru>

Cc: 574988@bugs.debian.org

Subject: Re: Bug#574988: Video access much slower than kvm-72 or any "snapshot" versions

Date: Tue, 23 Mar 2010 12:57:35 -0500

retitle 574988 kvm: cirrus video slower than snapshots
close 574988
thanks

On Mon, Mar 22, 2010 at 09:06:47PM +0300, Michael Tokarev wrote:
> I just tried it with 0.12.3+dfsg-4 (the one that entered -testing today).
> I see almost instant scrolling in winXP and w2k3 cmd window.  `dir' in
> C:\Windows directory takes a few fractions of a second to scroll.  I even

> > processor	: 0
> > vendor_id	: AuthenticAMD
> > cpu family	: 15
> > model		: 75
> > model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
> 
> One thing I notice is that my CPU is quite a bit faster than this:
> mine is running at 2.5GHz.  So that may explain the difference between
> your 1-2s/page with my less than 0.5s/page, in case of bad matching of
> color depth, but the difference is still larger than I'd expect based
> solely on cpu speed (mine is of the same generation, Athlon x2 64).

It's still a reasonably fast processor ;) It runs at 2GHz but slows
down to 1000MHz and 1800MHz depending on load.

My Windows installs under qemu-kvm date back to early 2007. This makes
them over 3 years old. In this time qemu-kvm has changed its "hardware
signature" to the OS a few times and it was always using the default
cirrus emulation.

Now, I've tried the "new" -vga std and amazingly video speed is back
to normal. I have tested at 1400x1050 and have seen no difference
between color depths (16, 24 or 32 bit). All function perfectly and
almost instant scrolling.

So I think the culprit may be using cirrus video at max resolution
(1280x1024 16-bit). Heck, I can't even use same bit depth as desktop
with cirus - native would be 1920x1080 32-bit.

Do you happen to know if there is any particular reason why `-vga std`
is not the new default options for qemu-kvm?

- Adam

PS. I'm retitling this bug to something that is more
descriptive. Closing it as well as I don't think there will be lots of
work done in cirrus emulation code anyway considering there is the std
video driver that works so much better.

-- 
Adam Majer
adamm@zombino.com

Message #36 received at 574988@bugs.debian.org (full text, mbox, reply):

From: Michael Tokarev <mjt@tls.msk.ru>

To: 574988@bugs.debian.org

Subject: reopen 574988

Date: Thu, 03 Jun 2010 19:09:37 +0400

unarchive 574988
reopen 574988
retitle 574988 cirrus emulation is slow for some guests in 0.12
tags 574988 - moreinfo
thanks

Reopening the bug, since the problem (cirrus vga
emulation) is actually present.  It does not affect
all guests equally, or maybe it does not happen on
all hosts, but it is definitely here.  To the point
when running linux guest in (default) SDL window is
amost impossible.

/mjt

Message #43 received at 574988-close@bugs.debian.org (full text, mbox, reply):

From: Michael Tokarev <mjt@tls.msk.ru>

To: 574988-close@bugs.debian.org

Subject: Bug#574988: fixed in qemu-kvm 0.14.0+dfsg-1~tls

Date: Thu, 24 Feb 2011 09:33:55 +0000

Source: qemu-kvm
Source-Version: 0.14.0+dfsg-1~tls

We believe that the bug you reported is fixed in the latest version of
qemu-kvm, which is due to be installed in the Debian FTP archive:

kvm_0.14.0+dfsg-1~tls_i386.deb
  to main/q/qemu-kvm/kvm_0.14.0+dfsg-1~tls_i386.deb
qemu-kvm-dbg_0.14.0+dfsg-1~tls_i386.deb
  to main/q/qemu-kvm/qemu-kvm-dbg_0.14.0+dfsg-1~tls_i386.deb
qemu-kvm_0.14.0+dfsg-1~tls.debian.tar.gz
  to main/q/qemu-kvm/qemu-kvm_0.14.0+dfsg-1~tls.debian.tar.gz
qemu-kvm_0.14.0+dfsg-1~tls.dsc
  to main/q/qemu-kvm/qemu-kvm_0.14.0+dfsg-1~tls.dsc
qemu-kvm_0.14.0+dfsg-1~tls_i386.deb
  to main/q/qemu-kvm/qemu-kvm_0.14.0+dfsg-1~tls_i386.deb
qemu-kvm_0.14.0+dfsg.orig.tar.gz
  to main/q/qemu-kvm/qemu-kvm_0.14.0+dfsg.orig.tar.gz



A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 574988@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Michael Tokarev <mjt@tls.msk.ru> (supplier of updated qemu-kvm package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Format: 1.8
Date: Wed, 23 Feb 2011 13:40:53 +0300
Source: qemu-kvm
Binary: qemu-kvm qemu-kvm-dbg kvm
Architecture: source i386
Version: 0.14.0+dfsg-1~tls
Distribution: unstable
Urgency: low
Maintainer: Jan Lübbe <jluebbe@debian.org>
Changed-By: Michael Tokarev <mjt@tls.msk.ru>
Description: 
 kvm        - dummy transitional package from kvm to qemu-kvm
 qemu-kvm   - Full virtualization on x86 hardware
 qemu-kvm-dbg - Debugging info for qemu-kvm
Closes: 574063 574988 575720 603424 604034
Changes: 
 qemu-kvm (0.14.0+dfsg-1~tls) unstable; urgency=low
 .
   * 0.14.0 release:
    - much improved vga speed (closes: #575720, #574988)
    - other bugs (closes: #574063, #603424, #604034)
   * removed a ton of old patches that went upstream
   * refreshed some patches to apply cleanly to new code
   * introduced vgabios (0.6c+ca056d8e77) patch and use that
     instead of kvm/vgabios/.  Now we can use separate vgabios package
     (bios files changed. Now we don't ship vgabios.bin anymore)
   * added fix-configure-bin-symlinks.patch to fix ./configure in
     case all blobs in the source are removed
   * don't ship kvmtrace anymore (does not exist upstream?)
   * update debian/rules for the new package layout (esp. "clean" target)
   * enable hda (guest) audio device
   * apply isa-bus:-Remove-bogus-IRQ-sharing-check-ee951a.diff
     from upstream. this makes >4 com ports usable again
     (also removes old isa-refine-irq-reservations.patch)
   * use external seabios package and depend on it (>> 0.6.1.2)
   * move bridge-utils and iproute from Depends to Recommends
   * build-depend on xfslibs-dev (for xfs-specific ioctls, not for the library)
   * switch to 3.0 (quilt) format (and remove clean-patched target)
   * removed 06_no_system_linux_kvm_h.patch (kvm/* isn't used anymore)
   * depend on qemu-utils >> 0.14, and deprecate kvm-img, kvm-nbd and kvm-io
     (provide script wrappers for them that prints a warning and executes a
     real tool from qemu-utils)
Checksums-Sha1: 
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 9a61dfb468584283187848e7ed45ab8b5dfc8129 4363642 qemu-kvm_0.14.0+dfsg.orig.tar.gz
 06dea1f1a4d1538c6481c5a1b3a95320ad1e41a6 104182 qemu-kvm_0.14.0+dfsg-1~tls.debian.tar.gz
 1c48adf032281b989d8d13c7e59b8ccb3f61a131 1212926 qemu-kvm_0.14.0+dfsg-1~tls_i386.deb
 e5426c1e9ddfea89c7165e7da23a08c47e15dbfa 2675908 qemu-kvm-dbg_0.14.0+dfsg-1~tls_i386.deb
 184825fc060a9f1deb9406696e458ff71e0241a1 8230 kvm_0.14.0+dfsg-1~tls_i386.deb
Checksums-Sha256: 
 24d95ceae376a2672a222b164996f3bdbbcf31a9069daf2afa4b0889cb01cd3d 1695 qemu-kvm_0.14.0+dfsg-1~tls.dsc
 bf734bfa1854ffc66329b411a5b398f2eb2fbcebee3dcf8d6e5e5e08ea1cecdf 4363642 qemu-kvm_0.14.0+dfsg.orig.tar.gz
 e50a0da01ec142b225110d03c5e7917d418d095031aae52981b3c06af04fbb2a 104182 qemu-kvm_0.14.0+dfsg-1~tls.debian.tar.gz
 1f8a55d90362d4612106df09ad08a26aca6cd9bec15704772be24c4b4f6a8313 1212926 qemu-kvm_0.14.0+dfsg-1~tls_i386.deb
 15255612c96b0ea12a3264ae079777b749afc0a247f8fe997f70a10a173dede2 2675908 qemu-kvm-dbg_0.14.0+dfsg-1~tls_i386.deb
 b5a5aeb0f4fe6c1bf69fb34a0bab68124cc5708ba25c4366b6577d24a771b8c0 8230 kvm_0.14.0+dfsg-1~tls_i386.deb
Files: 
 6dadfe75e60032db4d8045b84b1baf36 1695 misc optional qemu-kvm_0.14.0+dfsg-1~tls.dsc
 ced8842b9cfa928787d2a908680eec44 4363642 misc optional qemu-kvm_0.14.0+dfsg.orig.tar.gz
 35dd17e6bdb0cd7725b84f7e7cd493f4 104182 misc optional qemu-kvm_0.14.0+dfsg-1~tls.debian.tar.gz
 03e541b8e1898e74f3901ffa2849dfca 1212926 misc optional qemu-kvm_0.14.0+dfsg-1~tls_i386.deb
 acb47edfc841cc14d8d6f74092cc98c6 2675908 debug extra qemu-kvm-dbg_0.14.0+dfsg-1~tls_i386.deb
 0e978481c833c17dd34c24e41059f006 8230 oldlibs extra kvm_0.14.0+dfsg-1~tls_i386.deb

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