https://wiki.xenproject.org/api.php?action=feedcontributions&user=ArielGlenn&feedformat=atomXen - User contributions [en]2024-03-29T01:35:35ZUser contributionsMediaWiki 1.31.3https://wiki.xenproject.org/index.php?title=Talk:Main_Page&diff=6830Talk:Main Page2013-03-24T09:48:37Z<p>ArielGlenn: Created page with "Pleas consider upgrading to a more recent version of MediaWiki. Current is 1.20.2 I believe; a number of security fixes as well as new features have been added since the version…"</p>
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<div>Pleas consider upgrading to a more recent version of MediaWiki. Current is 1.20.2 I believe; a number of security fixes as well as new features have been added since the version in sue here, 1.15. Thanks. -- [[User:ArielGlenn|ArielGlenn]] 09:48, 24 March 2013 (UTC)</div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User:Adam_Drake&diff=6829User:Adam Drake2013-03-24T09:46:06Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User:WilburnPiechowski4&diff=6828User:WilburnPiechowski42013-03-24T09:45:29Z<p>ArielGlenn: Blanked the page</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User:Herbal_Vaporizers&diff=6827User:Herbal Vaporizers2013-03-24T09:45:07Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User_talk:TommieCristina34&diff=6826User talk:TommieCristina342013-03-24T09:44:46Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User_talk:VanNicewonger211&diff=6825User talk:VanNicewonger2112013-03-24T09:44:30Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User_talk:BeulahLiljeberg17&diff=6824User talk:BeulahLiljeberg172013-03-24T09:43:53Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User_talk:GaynellHuston678&diff=6823User talk:GaynellHuston6782013-03-24T09:43:37Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User_talk:JosueMadonna09&diff=6822User talk:JosueMadonna092013-03-24T09:42:38Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=User:LaurineSoucy1&diff=6821User:LaurineSoucy12013-03-24T09:41:51Z<p>ArielGlenn: spam cleanup</p>
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<div></div>ArielGlennhttps://wiki.xenproject.org/index.php?title=Xen_Profiling:_oprofile_and_perf&diff=6820Xen Profiling: oprofile and perf2013-03-24T09:41:11Z<p>ArielGlenn: /* oprofile */</p>
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<div>''By Konrad Rzeszutek Wilk'' from [http://lists.xen.org/archives/html/xen-devel/2012-07/msg00531.html]<br />
<br />
== Summary ==<br />
<br />
I've been toying with some perf tools using the v3.5 kernel to get<br />
an idea of what is working and what not. The executive summary<br />
is that we should write a perf driver to interact with perf<br />
Linux subsystem; and also to enhance the perf library to support<br />
the --xen extensions (similar to how the --kvm exists). It might<br />
also require adding some new hypercalls, though the existing<br />
ones (the oprofile variant) could be retooled to use with perf.<br />
<br />
== perf ==<br />
<br />
What currently exists are two ways of collecting performance data<br />
in both dom0 and domU (and by that I also mean PVHVM). The easiest<br />
one is the '[https://perf.wiki.kernel.org/index.php/Main_Page perf]' <br />
toolkit which works nicely - except that it is<br />
using a timer mode - so not very accurate. However, if Xen is booted<br />
with 'vpmu=1' parameter and perf is used within a PVHVM guest - the<br />
data is much more accurate. So what would be good is to implement<br />
a non-timer variant (so some model of APIC emulation combined<br />
with collecting data in a oprofile ring and avoiding MSRs).<br />
<br />
== oprofile ==<br />
<br />
The good news is that the old performance system [http://oprofile.sourceforge.net oprofile] works<br />
with the non-timer variant with some patches. You could also<br />
run the oprofile in timer mode and get the same data that the 'perf'<br />
does. The patches for the oprofile have been in the past posted<br />
by Michael Petullo, and I created a git branch with them with<br />
some little changes (basically to make them work with the new<br />
kernel - they are still buggy though - rmmoding caused a crash).<br />
They are now at:<br />
<br />
: git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git devel/oprofile.v1<br />
<br />
I plan to tinker a bit with them so they aren't completely hacked in with <code><nowiki>#ifdef CONFIG_XEN</nowiki></code> but I do not have any plans to upstream them.<br />
I think the right direction is to make a new shiny perf driver.<br />
<br />
Anyhow, if you want to play and get some performance data, the steps<br />
are:<br />
<br />
* Get the latest kernel from Linus's tree. Merge the above mentioned git branch<br />
* Install oprofile. If you are using Fedora 17, the oprofile RPM already has the Xen enablement patches thanks to William Cohen (see [http://lists.xen.org/archives/html/xen-devel/2011-11/msg02181.html]). If you are using a different distro, get oprofile and apply the patch mentioned in the [http://www.flyn.org/patches/linux-xen-passive-oprofile/linux-3.0-xen-passive-oprofile.patch.gz URL].<br />
<br />
* Run it. This is what I've been doing:<br />
<br />
opcontrol --start --passive-domains=2,3 <br />
--passive-images=/mnt/lab/nettest/vmlinux-pvhvm,/mnt/lab/nettest/vmlinux-pvhvm <br />
--xen=/data/xen-syms --vmlinux=/data/vmlinux --callgraph=5<br />
<br />
A co-worker mentioned that to get the exact data from the guest<br />
(which is not what I was using it for), your guest config file<br />
must contain this "magic":<br />
<br />
cpuid=['0xa:eax=0x07300403,ebx=0x00000004,ecx=0x00000000,edx=0x00000603'<br />
<br />
for HVM guests. For PV guests the data shows up just fine.<br />
<br />
<br />
[[Category:Xen]]<br />
[[Category:Developers]]<br />
[[Category:PVOPS]]<br />
[[Category:Performance]]</div>ArielGlenn