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Bug#642729: marked as done (linux-image-2.6.32-5-686: bad ssd performance with squeeze kernel 2.6.32)

Your message dated Sun, 29 May 2016 21:24:52 +0100
with message-id aa90e016-b80a-4bd5-b910-3d69fd3b9373@decadent.org.uk
and subject line Closing bugs assigned to linux-2.6 package
has caused the Debian Bug report #642729,
regarding linux-image-2.6.32-5-686: bad ssd performance with squeeze kernel 2.6.32
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@bugs.debian.org
immediately.)


-- 
642729: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=642729
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: linux-image-2.6.32-5-686
Version: 2.6.32-35squeeze2jba
Severity: normal


After adding a ssd (OCZ Vertex Plus 60GB) to my squeeze system (debian kernel 2.6.32) 
I was disappointed about its performance, as it was advertised with 185 MB/s.

/dev/sdb:
 Timing buffered disk reads: 214 MB in  3.01 seconds =  71.04 MB/sec
 
However, when running recent knoppix (kernel 3.0.4) I got the expected performance:

/dev/sdb:
 Timing buffered disk reads: 490 MB in  3.00 seconds = 163.07 MB/sec
 
After googling, I found that this has been reported before:

http://www.archivum.info/linux-ide@vger.kernel.org/2010-02/00243/bad-performance-with-SSD-since-kernel-version-2.6.32.html

It seems that early versions of kernel 2.6.32 have a bug that results in bad performance of some
ssds (maybe all, at least the 'OCZ Vertex Plus 60GB' and the 'Super Talent Ultradrive GX MLC 64GB').
Reverting the patch as described in the discussion solved the problem for me. I now have the 
desired performance.

Thus, I would suggest to revert the patch "block: improve queue_should_plug() by looking at 
IO depths" in kernel 2.6.32 for squeeze in order to get full ssd performance. I think the bugfix 
is important as an increasing number of users havs  ssds and the bug more or less breaks ssd 
performance in squeeze.

Juergen



-- System Information:
Debian Release: 6.0.2
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 2.6.32-5-686 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages linux-image-2.6.32-5-686 depends on:
ii  coreutils                     8.5-1      GNU core utilities
ii  debconf [debconf-2.0]         1.5.36.1   Debian configuration management sy

linux-image-2.6.32-5-686 recommends no packages.

Versions of packages linux-image-2.6.32-5-686 suggests:
pn  fdutils                       <none>     (no description available)
pn  ksymoops                      <none>     (no description available)
pn  linux-doc-2.6.32-5-686 | linu <none>     (no description available)
pn  linux-image-2.6.32-5-686-dbg  <none>     (no description available)

-- debconf information:
  linux-image-2.6.32-5-686/preinst/failed-to-move-modules-2.6.32-5-686:
  linux-image-2.6.32-5-686/postinst/kimage-is-a-directory:
  linux-image-2.6.32-5-686/postinst/depmod-error-initrd-2.6.32-5-686: false
  linux-image-2.6.32-5-686/postinst/ignoring-do-bootloader-2.6.32-5-686:
  linux-image-2.6.32-5-686/postinst/old-system-map-link-2.6.32-5-686: true
  linux-image-2.6.32-5-686/postinst/missing-firmware-2.6.32-5-686:
* linux-image-2.6.32-5-686/preinst/overwriting-modules-2.6.32-5-686: false
  linux-image-2.6.32-5-686/prerm/removing-running-kernel-2.6.32-5-686: true
  linux-image-2.6.32-5-686/postinst/depmod-error-2.6.32-5-686: false
  linux-image-2.6.32-5-686/postinst/old-dir-initrd-link-2.6.32-5-686: true
  linux-image-2.6.32-5-686/preinst/abort-overwrite-2.6.32-5-686:
* linux-image-2.6.32-5-686/preinst/already-running-this-2.6.32-5-686:

--- End Message ---
--- Begin Message --- 
Version: 3.4.1-1~experimental.1+rm

Debian 6.0 Long Term Support has ended, and the 'linux-2.6' source
package will no longer be updated.  This bug was reassigned to the
'linux' source package earlier today, but I am now closing it on the
assumption that it does not affect the kernel versions in newer Debian
releases.

If you can still reproduce this bug in a newer release, please reopen
the bug report and reassign it to 'src:linux' and the affected version
of the package.  You can find the package version for the running
kernel by running:

    uname -v

or the versions of all installed kernel packages by running:

    dpkg -l 'linux-image-[34]*' | grep ^.i

and looking at the third column.

I apologise that we weren't able to provide a specific resolution for
this bug.

Ben.

-- 
Ben Hutchings - Debian developer, member of Linux kernel and LTS teams

--- End Message ---
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